Materials and methods for chemically selective multi-wavelength photopolymerization

Abstract

A wavelength-selective and intensity-selective approach to imbue photopolymers with selective solubility for various applications is provided herein. For example, a material of the present embodiments can have two different curing mechanisms that, depending on the curing mechanism(s) used, form a solid that is either soluble or insoluble in a chosen solvent. By exposing an epoxide- and acrylate-based resin to light at different wavelengths, independent control of acrylate and epoxide conversion, and therefore the solubility of the resulting solid, can be achieved. This photopolymer allows for the creation of dissolvable and recyclable supports with a single resin when printed using multi-wavelength digital light processing (DLP). Moreover, these multi-wavelength selecting solubility characteristics can be combined with grayscale control of light intensity to produce complete spatial control of dissolution kinetics.

Description

MATERIALS AND METHODS FOR CHEMICALLY SELECTIVE MULTI- WAVELENGTH PHOTOPOLYMERIZATIONGOVERNMENT RIGHTS

[0001] This invention was made with government support under DGE2141064 awarded by the National Science Foundation, and N00014-23-1-2499 awarded by the Office of Naval Research. The government has certain rights in the invention.

[0002] The present disclosure claims priority7to and the benefit of U.S. Provisional Application 63 / 724,900, entitled "Materials and Methods of Chemically Selective MultiWavelength Photopolymerization," filed on November 25, 2024, the content of which is incorporated by reference herein in its entirety7.FIELD

[0003] The present disclosure relates to materials and methods for selective photopolymerization, and more particularly relates to systems and methods for forming and using a resin that exhibits wavelength-selective solubility upon exposure to light of varying wavelengths and its applications.BACKGROUND

[0004] Additive manufacturing (AM) has emerged as a transformative technology7that enables the creation of complex three-dimensional objects through layer-by-layer material deposition. Among the various AM technologies, vat photopolymerization (VP) has gained widespread adoption across industries including jewelry7, dentistry, aerospace, and consumer products due to its ability to produce high-resolution parts with excellent surface finish. VP processes utilize liquid photopolymer resins that are selectively cured using light sources to build three-dimensional structures with precise geometric control. The technology encompasses various techniques including stereolithography, digital light processing, and continuous liquid interface production, each offering distinct advantages for different applications.

[0005] Despite the advantages of VP technology, the process faces limitations related to support structure requirements during printing. Support structures are typically needed to stabilize overhanging features, bridge gaps, and prevent part distortion during the layer-by-layer build process. These support structures are generally fabricated from the same material as the primary part, creating challenges for removal after printing is complete. Manual support removal is labor-intensive, time-consuming, and can damage delicate features or compromise surface quality of the finished part. The removal process often requires specialized tools and skilled operators, adding cost and complexity to the manufacturing workflow. Furthermore, support structures represent material waste since they cannot typically be reused or recycled in conventional VP processes. The challenges associated with support removal become particularly pronounced when manufacturing complex geometries with internal cavities, intricate channels, or enclosed volumes where physical access for support removal is limited or impossible. These geometric constraints can prevent the production of certain part designs that would otherwise be feasible with the resolution and material capabilities of VP technology. Additionally, the interface between support structures and the primary part often results in surface imperfections that require postprocessing operations such as sanding, polishing, or chemical treatment to achieve the desired surface quality. Such post-processing steps further increase manufacturing time and cost while potentially introducing dimensional variations or compromising part integrity.

[0006] No other AM strategies can emulate the low-cost, fast, high-quality nature of traditional VP. However, some AM technologies, such as selective laser sintering (SLS) and fused deposition modeling (FDM), can eliminate problems associated with support removal by using powder beds or dissolvable supports. As for VP, multiple attempts have been made to incorporate more easily removable support materials, such as using soluble plastics or ice as supports. However, these methods may use multiple different resins or sacrificial materials and mechanically complex systems to switch between them, resulting in slow, complex printing processes that have failed to successfully achieve their goals.

[0007] Accordingly, there is a need for systems and materials that enable automated support removal without manual intervention, reduce material waste through support structure recycling, and expand the range of manufacturable geometries by eliminating constraints associated with support accessibility.SUMMARY

[0008] The presently disclosed embodiments generally relate to resin matenals and methods for chemically selective multi-wavelength and grayscale photopolymerization. Suchmaterials enable wavelength-selective or dosage-selective solubility properties that can be controlled through exposure to different wavelengths or dosages of light, allowing for the creation of structures with regions that exhibit different dissolution behaviors in various solvents. For example, a photocurable material of the present embodiments can be exposed to two different curing mechanisms that, depending on the curing mechanism(s) used, can form a solid that is either soluble or insoluble in a chosen solvent. This functionality may be made possible by epoxide and acrylate groups linked via a bifunctional monomer. With this new material, fully automated support removal, increased print geometry possibilities, and recycling of support material may all be demonstrated. By using multi-wavelength or grayscale digital light processing (DLP) 3D printing, this material can be used for applications that will impact manufacturing for dentistry, jewelry, fashion, and robotics applications. These materials and methods provide solutions for additive manufacturing applications, particularly in the area of dissolvable support structures, while also offering capabilities for controlled release applications in drug delivery and other fields.

[0009] In accordance with some embodiments, the ability to create materials with spatially controlled dissolution properties through wavelength-selective or dosage-selective photopolymerization can present advantages in automated support removal for three-dimensional printing processes. Additionally, the capability to recycle dissolved support material back into the printing process can provide sustainability benefits and reduce material waste. The grayscale control of light intensity can further enable precise spatial control over dissolution kinetics, opening applications in pharmaceutical and biomedical fields where controlled release profiles are desired.

[0010] In an aspect, embodiments relate to a resin material comprising one or more monofunctional monomers that are configured to photocure into a dissolvable material using a first polymerization mechanism. The resin material further comprises one or more multifunctional monomers having one or more chemical groups that are capable of reacting via a mechanism different than the first polymerization mechanism of the one or more monofunctional monomers. The resin material also comprises one or more photoinitiators, co-initiators, or photosensitizers. The resin material comprises a first plurality of material regions having a first dissolution rate that dissolve in a plurality of solvents after the resin material is exposed to light at a first range of intensities, durations of exposure, or dosages. The resin material comprises a second plurality of material regions with a second dissolution rate in the plurality’ of solvents that would dissolve the first plurality of material regions afterthe resin material is exposed to light at a second range of intensities, durations of exposure, or dosages, the second dissolution rate being different than the first dissolution rate.

[0011] One or more of the following features can be included. The second dissolution rate can be lower than the first dissolution rate such that the first plurality of material regions are configured to be dissolved on a timescale where the second plurality of material regions undergo negligible dissolution. The second plurality of material regions can have a dissolution rate that is effectively zero. The light in the first range of intensities or durations of exposure can be at the same wavelength as light in the second range of intensities or durations of exposure. The resin material can be at least one of iteratively or simultaneously exposed to different dosages of patterned light to spatially segregate at least one of a soluble region or an insoluble region within the plurality of material regions. The resin material can be configured to be used in a 3D printing process to create 3D structures with separate regions that are soluble and insoluble. The additive can comprise about 1% to about 50% of the resin material composition and acts as a primary material imparting differential solubility. The first polymerization mechanism can comprise free radical polymerization and the mechanism different than that of the one or more monofunctional monomers can comprise cationic ring-opening polymerization. The resin material can further comprise a free radical inhibitor selected from the group comprising hydroquinones, stable radicals, radical quenchers, and chain transfer agents. The one or more monofunctional monomers can comprise isobomyl acrylate and the one or more multifunctional monomers can comprise epoxide crosslinkers. The photosensitizer can be selected from the group consisting of methoxy thioxanthone, isopropylthioxanthone. 2-ethy 1-9, 10-dimethoxy anthracene, anthracene, chlorophyll, camphorquinone, and 5,7-diiodo-3-butoxy-6-fluorone. The resin material can further comprise one or more bridging monomers that have one or more of the chemical groups of the one or more multifunctional monomers and one or more additional chemical groups capable of photocuring with the one or more monofunctional monomers. The resin material can further comprise a base quencher added in a molar amount less than a molar amount of a photoacid generator to control extent of cationic polymerization. The base quencher can be selected from the group consisting of tertiary amines, pyridine, alcohols, quaternary ammonium salts, organic bases, and ammonium hydroxide. Spatial control of light dosage can enable control over local degree of solubility ranging from a maximum rate of solubility along a range of dissolution rates that extend down to zero.

[0012] In another aspect, embodiments relate to a method of forming a three-dimensional object comprising irradiating a resin material with radiation of a specific wavelength at different intensities or durations of exposure to form a plurality of material regions with different chemical connectivities. A first of the plurality of material regions is capable of dissolving in a plurality of solvents, and a second of the plurality of material regions exhibits dissolution rates in said plurality of solvents that differs from the dissolution rates of the first plurality of material regions in the plurality of solvents.

[0013] One or more of the following features can be included. Irradiating the resin material with radiation can occur in a vat photopolymerization three-dimensional printing process to create three-dimensional structures having soluble and insoluble regions. The vat photopolymerization can comprise digital light processing using a digital micromirror device for spatial light patterning. The method can further comprise dissolving one or more of the plurality of material regions with a fluid comprising one or more monomer components of the resin material. The method can further comprise recycling the plurality of material regions by incorporating the fluid with dissolved material regions into a new7resin formulation. The method can further comprise applying a heat treatment to alter the dissolution rates of one or more of the plurality of material regions. The heat treatment can be performed at a temperature ranging from about 50°C to about 180°C. The heat treatment can be performed in a non-reactive, non-volatile liquid medium to achieve neutral or near-neutral buoyancy conditions. The method can further comprise performing one or more of radical acrylate polymerization, ring opening of epoxides and oxetanes, radical thiol-ene polymerization, ring opening of oxazolines. ionic thiol-epoxide polymerization, ionic thiolisocyanate polymerization, ring opening metathesis polymerization, or hydrosilylation on one or more of the first of the plurality of material regions or the second of the plurality of material regions.

[0014] In another aspect, embodiments relate to a resin material comprising one or more monofunctional monomers and one or more photoinitiators or photosensitizers that are capable of photocuring into a dissolvable material. The resin material further comprises one or more monomers having one or more chemical groups capable of undergoing a polymerization mechanism different than that of the one or more monofunctional monomers. The resin material also comprises one or more photoinitiators or photosensitizers that are configured to photocure: (i) said additional chemical groups to form a thermoset material, or (ii) the one or more monofunctional monomers and the said additional chemical groups toform a thermoset material. The resin material comprises a solid with a first plurality of material regions that are capable of dissolving in a plurality of solvents after the resin material is exposed to light at a first wavelength, and the resin material comprises a solid with a second plurality of material regions having a different dissolution rate in the plurality of solvents that would dissolve the first plurality of material regions of the solid after the resin material is exposed to light at a second wavelength.

[0015] One or more of the following features can be included. The second plurality of material regions of the solid can have a dissolution rate that is lower than a dissolution rate of the first plurality of material regions of the solid such that the first plurality of material regions are configured to be dissolved on a timescale where the second plurality of material regions undergoes negligible dissolution. The second plurality of material regions can have a dissolution rate that is effectively zero. The resin material can be configured to be used to print three-dimensional objects wherein different spatial regions of the three-dimensional object are exposed to different wavelengths of light during a printing process such that the different regions of the three-dimensional object have different dissolution rates. The first plurality of material regions of the solid can be soluble in one or more components of the resin material, and the second plurality of material regions of the solid can resist dissolution in the one or more components of the resin material. The solid can be configured to be used as a component of a second resin material that achieves the same differential solubility as the resin material. The resin material can further comprise a multifunctional monomer having a plurality of the one or more chemical groups of the one or more monomers. The multifunctional monomer can have zero or one or more functional groups that allow the multifunctional monomer to react with the one or more monofunctional monomers. The one or more monofunctional monomers and the one or more photoinitiators or photosensitizers can cure via a free radical mechanism. The resin material can further comprise one or more bridging monomers that have one or more of the chemical groups of the one or more monomer and one or more additional chemical groups capable of photocuring with the one or more monofunctional monomers. The one or more monofunctional monomers can comprise an acrylate, a methacry late, or an acrylamide. The one or more monomers that have the one or more additional chemical groups can cure via an ionic mechanism. The resin material can further comprise one or more of: i) a weak base added in a molar amount less than a molar amount of a photoacid generator for a cationic mechanism, or ii) a weak acid added in a molar amount less than a molar amount of a photobase generator for an anionic mechanism.The one or more additional chemical groups can comprise an epoxide ring. The first wavelength can be about 405 nm and the second wavelength can be about 365 nm.

[0016] In another aspect, embodiments relate to a method of forming a three-dimensional object comprising irradiating a resin material with radiation of a plurality of wavelengths in a plurality of locations along the resin material to form a solid with a plurality of material regions with different chemical connectivities. A first of the plurality of material regions is capable of dissolving in a plurality of solvents, and a second of the plurality of material regions exhibits dissolution rates in said plurality of solvents that differs from the dissolution rates of the first plurality of material regions in the plurality of solvents.Irradiating the plurality of locations is performed either iteratively or simultaneously.

[0017] One or more of the following features can be included. Irradiating the resin material with radiation can occur in a vat photopolymerization three-dimensional printing process to create three-dimensional structures having soluble and insoluble regions. The vat photopolymerization can comprise digital light processing using one or more of a digital micromirror device for spatial light patterning, an LCD, or a laser. The method can further comprise dissolving one or more of the plurality’ of material regions with a fluid comprising one or more monomer components of the resin material. The method can further comprise recycling the plurality of material regions by incorporating the fluid with dissolved material regions into a new resin formulation. A heat treatment can be applied to alter the dissolution rates of one or more of the plurality of material regions. The heat treatment can be performed at a temperature ranging from about 50°C to about 180°C. The heat treatment can be performed in a non-reactive, non-volatile liquid medium to achieve neutral or near-neutral buoyancy conditions. The resin material can comprise one or more monofunctional monomers and one or more photoinitiators or photosensitizers that are capable of photocuring into a dissolvable material, and one or more monomers that have one or more chemical groups capable of photocuring with one or more of the monofunctional monomers, with the one or more monofunctional monomers having one or more additional chemical groups capable of undergoing a polymerization mechanism different than that of the one or more monofunctional monomers. The plurality of wavelengths can comprise a first wavelength of approximately 405 nm and a second wavelength of approximately 365 nm.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1A is a schematic diagram illustrating a vat photopolymerization process of a resin showing different light exposure conditions and resulting material properties with a first inset (i) showing the reaction and resultant material that is formed when exposing the resin to visible light, and a second inset (ii) showing the reaction and resultant material that is formed when exposing the resin to ultraviolet (UV) light;

[0019] FIG. IB is a process flow diagram illustrating a 3D printing process using a resin material with wavelength-selective solubility properties;

[0020] FIG. 2A is a portion of a sequence diagram of a selective photopolymerization of a resin material showing the resin material;

[0021] FIG. 2B is a perspective view of the resin material of FIG. 2 A in a flask after exposure to visible light;

[0022] FIG. 2C is a perspective view of the flask of FIG. 2B after 40-60 minutes have elapsed showing that the resin material has fully dissolved;

[0023] FIG. 2D is perspective view of the resin material of FIG. 2 A in a flask after exposure to ultraviolet light;

[0024] FIG. 2E is a perspective view of the flask of FIG. 2D after 60 or more minutes have elapsed showing that the resin material remains undissolved;

[0025] FIG. 3A is a perspective view of one embodiment of a printed assembly design prepared using the techniques of the present embodiments;

[0026] FIG. 3B is a perspective view of the printed assembly design of FIG. 3 A in support material;

[0027] FIG. 3C is a perspective view of the printed assembly design of FIG. 3 B after support material dissolution;

[0028] FIG. 3D is a perspective view of one embodiment of a lattice with overhang design prepared using the techniques of the present embodiments;

[0029] FIG. 3E is a perspective view of the lattice with overhang design of FIG. 3D in support material;

[0030] FIG. 3F is a perspective view of the lattice with overhang design of FIG. 3E after support material dissolution;

[0031] FIG. 3G is a perspective view of one embodiment of a volumetric packing arrangement prepared using the techniques of the present embodiments;

[0032] FIG. 3H is a perspective view of the volumetric packing arrangement of FIG. 3G in support material;

[0033] FIG. 31 is a perspective view of the volumetric packing arrangement of FIG. 3H after support material dissolution;

[0034] FIG. 3J is a perspective view of one embodiment of a dissolvable interface prepared using the techniques of the present embodiments;

[0035] FIG. 3K is a perspective view of the dissolvable interface of FIG. 3 J in support material;

[0036] FIG. 3L is a perspective view of the dissolvable interface of FIG. 3K after support material dissolution;

[0037] FIG. 4A is a perspective view of an embodiment of a denture base print with supports prepared by the techniques of the present embodiments;

[0038] FIG. 4B is a perspective view of the denture base print of FIG. 4A with a corresponding support geometry;

[0039] FIG. 4C is a perspective view of the denture base print of FIG. 4B with the support geometry dissolved;

[0040] FIG. 4D is a perspective view of a final denture base of FIG. 4C;

[0041] FIG. 4E is a perspective view of another embodiment of a denture base print with supports prepared by the techniques of the present embodiments;

[0042] FIG. 4F is a perspective view of the denture base print of FIG. 4E with a corresponding support geometry;

[0043] FIG. 4G is a perspective view of a final denture base of FIG. 4F;

[0044] FIG. 5A is a transparent perspective view7of a drug core-shell structure of the present embodiments;

[0045] FIG. 5B is a top view of the drug core-shell structure of FIG. 5A;

[0046] FIG. 5C is a degradation curve showing percentage of material of the structure of FIG. 5A degraded over time;

[0047] FIG. 6 is a process flow diagram illustrating a recycling process for resin material; and

[0048] FIG. 7 is a schematic diagram of a computing system for implementing the techniques described herein.DETAILED DESCRIPTION

[0049] Certain embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the systems, devices, related components (e.g., resin materials, photoinitiators, photosensitizers, multifunctional monomers, monofunctional monomers, crosslinking additives, and wavelength-selective photopolymerization systems), and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present disclosure is defined solely by the claims. The features illustrated or described in connection with one exemplary' embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present disclosure. Further, to the extent features, wavelengths, regions, materials, or the like are described as being "first," "second," third," etc., and / or "soluble," "insoluble," "dissolvable," etc., such numerical and / or functional ordering / identification is generally arbitrary, and thus such numbering can be interchangeable unless indicated or otherwise understood by those skilled in the art to not be interchangeable. While terms like "wavelength-selective" and "grayscale" are used herein, they are primarily used as a point of reference for describing different photopolymerization mechanisms and light exposure conditions. Accordingly, no meaning should be attributed to a specific wavelength or intensity beyond distinguishing one polymerization mechanism from another unless explicitly indicated. For example, what is referred to herein as a first wavelength may be considered a second wavelength in operation, and thus, likewise, what is referred to herein as a second wavelength may be considered a first wavelength in operation.

[0050] The figures provided herein are not necessarily to scale, although a person skilled in the art will recognize instances where the figures are to scale and / or what a typical size is when the drawings are not to scale. Further, to the extent that linear or circular dimensions or shapes are used or described herein, such dimensions are not intended to limit the types ofshapes or sizes of such devices, components, etc. A person skilled in the art will recognize that an equivalent to such linear and / or circular dimensions or shapes can be easily determined for any geometric shape (e.g., references to widths and diameters being easily adaptable for circular and linear dimensions, respectively, by a person skilled in the art). While in some embodiments movement of one component is described with respect to another, a person skilled in the art will recognize that other movements are possible. Further, to the extent arrows are used to describe a direction a component can expand or move, these arrows are illustrative and in no way limit the direction the respective component can expand or move. A person skilled in the art will recognize other ways and directions for creating the desired tension or movement.

[0051] Still further, in the present disclosure, like-numbered components of various embodiments generally have similar features when those components are of a similar nature and / or serve a similar purpose, unless otherwise noted or otherwise understood by a person skilled in the art. To the extent the present disclosure includes prototypes, mock-ups, bench models, or the like, a person skilled in the art will recognize how to rely upon the present disclosure to integrate the techniques, systems, devices, and methods into a product, such as three-dimensional printing systems, vat photopolymerization equipment, multi-wavelength digital light processing printers, and controlled release drug delivery devices. A number of terms may be used throughout the disclosure interchangeably but will be understood by a person skilled in the art. By way of non-limiting example, the terms photosensitizer and coinitiator, dissolvable and soluble, thermoset and crosslinked, and wavelength-selective and multi-wavelength may be used interchangeably with one another. Moreover, it will be appreciated that although features may be discussed with respect to one embodiment within the present disclosure, these features can be applied to every7embodiment of the present disclosure where such feature would be supported.

[0052] To the extent terms like "approximately," "about," and "substantially" are used herein, a person skilled in the art will appreciate the scope those words convey in the context of their usage. In the context of wavelength-selective photopolymerization, obtaining a certain degree of wavelength precision, light intensity control, dissolution rates, and / or crosslink density, among other chemical and physical properties may be difficult, and thus use of terms like "approximately," "about," and "substantially" is intended to address this difficulty. A person skilled in the art will understand what constitutes how close a particular dimension or placement should be to still fall within the spirit of the quantification anddescription provided for herein. Even in instances where such terminology is not used, and a dimension or wavelength just includes the number or term (e.g., "365 nm" is used instead of "approximately 365 nm"), a person skilled in the art will appreciate that, unless explicitly indicated otherwise, terms like "approximately," "about," and "substantially" are applicable to those dimensions and terms as well. The foregoing notwithstanding, a person skilled in the art will appreciate that terms like "approximately," "about," and "substantially" at least encompass wavelengths, intensities, concentrations, and dissolution rates that are ±10%. 10°, etc. of the provided amount, or encompass dimensions that are ±5%, 5°, etc. of the provided amount, unless indicated otherwise or otherwise known to those skilled in the art. The present disclosure appreciates that a person skilled in the art, in view of the present disclosure, understands suitable placements for various features of the disclosed resin materials, photopolymerization systems, and related components of any of the same, and thus to the extent a particular wavelength, concentration, or exposure time is described, unless it is explicitly indicated that wavelength, concentration, or exposure time, a person skilled in the art will appreciate other wavelengths, concentrations, or exposure times that are possible without impacting the overall resin material or photopolymerization system.

[0053] The present disclosure relates to resin materials and methods for chemically selective multi-wavelength and grayscale photopolymerization that enable spatially controlled dissolution properties through wavelength-selective and dosage-selective light exposure. These resin materials can undergo different polymerization mechanisms when exposed to different wavelengths or dosages of light, resulting in regions with distinct solubility characteristics within a single material system. The disclosed materials can form thermoplastic regions that dissolve readily in various solvents when exposed to one w avelength or dosage of light, while simultaneously forming crosslinked thermoset regions that resist dissolution when exposed to a different w avelength or dosage of light. This wavelength-selective or dosage-selective behavior enables the creation of complex three-dimensional structures with integrated support materials that can be selectively removed through dissolution processes.

[0054] The resin materials disclosed herein can comprise monofunctional monomers that undergo photopolymerization to form dissolvable thermoplastic materials, multifunctional monomers that undergo photopolymerization to form crosslinked thermoset materials, and various photoinitiators or photosensitizers that enable wavelength-selective or dosage-selective activation of these different polymerization mechanisms. In some embodiments, theresin materials can include bridging additives that contain multiple reactive functional groups capable of covalently linking the different polymer networks formed during the photopolymerization processes. The resulting materials can exhibit spatially controlled dissolution behavior, where regions exposed to different wavelengths or dosages of light demonstrate markedly different solubility properties in the same solvent systems.

[0055] The wavelength-selective or dosage-selective photopolymerization approach can enable various manufacturing applications, including three-dimensional printing processes that utilize dissolvable support structures, drug delivery systems with controlled release profiles, and coating applications where selective dissolution properties are beneficial. The resin materials can be formulated to respond to specific wavelengths or dosages of light, allowing for precise spatial control over the final material properties through patterned light exposure. This approach can eliminate the need for multiple resin systems or complex material switching mechanisms that are typically associated with multi-material manufacturing processes.

[0056] The dissolution properties of the photopolymerized materials can be controlled through various parameters including light wavelength, light intensity, exposure duration, and post-processing conditions such as thermal treatment. In some embodiments, grayscale light exposure techniques can be employed to create continuous gradients in dissolution kinetics, enabling fine-tuned control over material solubility across different regions of a single structure. The resin materials can be dissolved in various solvent systems, including organic solvents, aqueous solutions, or even in the original monomer components to enable material recycling and reuse.

[0057] The photopolymerization mechanisms employed in these resin materials can include free radical polymerization, cationic ring-opening polymerization, anionic polymerization, and various other polymerization chemistries that can be selectively activated through wavelength-specific or dosage-dependent photoinitiators or photosensitizers. The materials can incorporate various additives such as base quenchers or acid quenchers to control the extent of polymerization in different regions and to prevent unwanted polymerization or crosslinking during processing. Post-processing treatments, including thermal curing, can be employed to enhance the differential solubility properties between regions exposed to different wavelengths of light.

[0058] MULTI-WAVELENGTH MATERIAL

[0059] Referring to FIG. 1A, a resin material 100 can be configured for multi-wavelength vat photopolymerization processes that can enable spatially controlled dissolution properties through wavelength-selective light exposure. The resin material 100 can include one or more monofunctional monomers and one or more photoinitiators or photosensitizers that are capable of photocuring into a dissolvable material when exposed to light at a first wavelength. The resin material 100 can also comprise one or more monomers, e.g., multifunctional monomers, in some embodiments, and one or more photoinitiators or photosensitizers that are capable of converting the resin material into a solid thermoset using a polymerization mechanism different than that of the one or more monofunctional monomers. Additionally, the resin material 100 can include an additive, e.g., a bridging monomer, that includes one or more monomers that have two or more separate chemical groups capable of covalently crosslinking polymers formed by one or more of the monofunctional monomer and the multifunctional monomer. As show n in FIG. 1A, the resin material 100 can undergo different polymerization pathways depending on the wavelength of light exposure, with visible light exposure leading to formation of a soluble thermoplastic material 102. as shown in in inset (i) and UV light exposure leading to formation of an insoluble thermoset material 104, as show n in inset (ii), both of w hich are discussed in greater detail below .

[0060] With continued reference to FIG. 1 A, the one or more multifunctional monomers in the resin material 100 can include at least one of a difunctional epoxide crosslinker or a multifunctional epoxide crosslinker. In some embodiments, the one or more multifunctional monomers can include a bridging monomer, with examples of bridging monomers being discussed in greater detail below-. The epoxide crosslinkers can undergo cationic ringopening polymerization when activated by appropriate photoinitiators, forming crosslinked thermoset networks that resist dissolution in solvents. The monofunctional monomers in the resin material 100 can undergo free radical polymerization to form thermoplastic polymer chains that remain dissolvable in various solvent systems. The resin material 100 can dissolve in regions where less monomer is polymerized, creating a gradient of dissolution properties based on the extent of polymerization achieved in different regions. The bridging additive or bridging monomer in the resin material 100 can contain both acrylate and epoxide functional groups, allowing for covalent linkage between the thermoplastic and thermoset polymer networks formed during the different polymerization processes. In some embodiments, the bridging monomer can include functional groups that can be the only suchgroups in the resin composition that are capable of undergoing a polymerization mechanism different from that of the monofunctional monomer, as discussed in greater detail below.

[0061] As illustrated in FIG. IB, the resin material 100 can be configured to be used in three-dimensional printing to create three-dimensional structures having soluble and insoluble regions. An example embodiment of a printing process 200 can begin with a 3D model 202 that undergoes slicing operations 204 to generate printable layers with defined regions for different wavelength exposures. During the printing step, the resin material 100 can be selectively exposed to UV and visible light 206 to form solid regions with different dissolution properties. The resin material 100 can be configured to be used in a 3D printing process where patterned light exposure creates spatially segregated regions with different solubility characteristics. Following the printing process, the resulting printed structures 208 can undergo post-processing steps including baking and dissolution 210 to remove support structures and reveal the final three-dimensional geometry 212. The multi-wavelength approach can enable the creation of complex internal geometries and overhanging features that would be difficult or impossible to achieve with traditional single-material vat photopolymerization processes.

[0062] In some embodiments, the resin material 100 can undergo sequential photopolymerization processes that result in materials with distinct dissolution behaviors. The resin material 100 can utilize alternative polymerization mechanisms including ringopening metathesis polymerization (ROMP) with norbomene-based monomers, thiol-ene reactions, Michael addition with amines, and other click reactions to achieve wavelength-selective material properties. These alternative polymerization mechanisms can provide additional flexibility in tailoring the dissolution characteristics and mechanical properties of the resulting materials. The ROMP mechanism can be particularly useful for creating materials with controlled degradation profiles, while thiol-ene reactions can provide rapid polymerization kinetics and excellent spatial resolution. The selection of specific polymerization mechanisms can be tailored based on the intended application and desired dissolution behavior of the final printed structures.

[0063] As depicted in FIGS. 2A-2E, the process begins with the resin material 100 in its initial state, and when exposed to visible light at 405 nm, as shown in FIGS. 2B-2C, the resin material 100 can undergo free radical polymerization to form a solid, dissolvable thermoplastic polymer that can fully dissolve in about 40 to about 60 minutes for a representative sample geometry. Conversely, when exposed to UV light at 365 nm, as shownin FIGS. 2D, 2E, the resin material 100 undergoes both free radical polymerization and cationic polymerization, resulting in a fully covalently crosslinked network that resists dissolution even after 60 or more minutes for the same representative sample geometry. The resin material 100 can be configured such that spatial segregation of soluble and insoluble regions occurs when the resin material 100 is at least one of iteratively exposed to light at the first wavelength and light at the second wavelength or simultaneously exposed to light at the first wavelength and light at the second wavelength, with the light at the first wavelength and the light at the second wavelength being patterned light. The photoinitiators or photosensitizers in the resin material 100 can be configured to shift the first wavelength to a higher value or shift the second wavelength to a higher value through the use of appropriate photosensitizing compounds. In some embodiments, the first wavelength and the second wavelength can be at an equal wavelength, with differential polymerization behavior achieved through varying light intensities, exposure durations, or the use of photosensitizers, free radical inhibitors, or acids or bases, that create temporal delays in polymerization initiation.

[0064] The post-processing procedures for the resin materials can involve thermal treatment protocols that enhance the differential solubility’ properties between regions exposed to different wavelengths of light during the photopolymerization process. The thermal curing mechanisms can promote continued polymerization of reactive species that remain unreacted after the initial light exposure, leading to increased crosslink density in regions that were exposed to UV wavelengths. The heat treatment procedures can be performed at temperatures ranging from about 50°C to about 180°C, or about 80°C to about 180°C, with the specific temperature and duration selected based on the desired degree of crosslinking and the thermal stability’ of the polymer components. In some embodiments, the thermal treatment can be conducted at approximately 150°C for a brief hold period to achieve optimal differential solubility between UV-exposed and visible light-exposed regions. The thermal curing process can activate dormant cationic initiators that were generated during UV exposure, enabling continued ring-opening polymerization of epoxide monomers even after the light source has been removed. In addition, in some embodiments, the thermal curing process can activate dormant free radical or ionic initiators that were an additive in the resin, in order to increase monomer conversion or allow further polymerization to take place at temperatures lower than would be possible without thermal initiators. These initiators can be photoinitiators or thermal initiators, which react at an elevated temperature to generatespecies that can initiate a polymerization reaction. If there is any free radical inhibitor or acid quencher or base quencher in the system, these inhibitors or quenchers can be used to overcome thermal initiation in regions where further polymerization is not desired. In some embodiments, the molar concentration of the added thermal initiator can be less than that of the respective inhibitor or quencher.

[0065] The role of temperature in achieving selective solubility can be related to the activation energy requirements for different polymerization mechanisms and the thermal stability of the various reactive species present in the resin formulation. For example, higher temperatures can provide the thermal energy to overcome activation barriers for cationic polymerization reactions, enabling continued crosslinking in regions that contain activated photoacid generators from the initial UV exposure. The temperature-dependent reaction kinetics can create a threshold effect where regions exposed to visible light undergo minimal additional crosslinking during thermal treatment, while regions exposed to UV light experience substantial crosslinking enhancement. In some embodiments, the thermal treatment temperature can be optimized to maximize the differential crosslinking between UV-exposed and visible light-exposed regions while avoiding thermal degradation of the polymer components. The thermal activation of cationic initiators can be time-dependent, with longer treatment times leading to higher degrees of crosslinking up to a maximum conversion limit determined by the stoichiometry and reactivity' of the available monomers.

[0066] The thermal treatment procedures can be performed using inert, non-reactive, nonvolatile fluid media. Some non-limiting examples can include fluoropolymer oil, silicone oil, or an ionic liquid that can achieve neutral buoyancy conditions that prevent gravitational deformation of the printed structures during the heating process. In some embodiments, the media may also be a non-reactive, non-volatile solid, such as sand or powder. The neutral buoyancy approach can eliminate distortion that might otherwise occur due to thermal expansion, softening of the polymer matrix, or gravitational forces acting on the heated structures. The non-reactive, non-volatile medium can provide uniform heat transfer throughout the printed parts while maintaining dimensional stability during the thermal curing process. In some embodiments, the non-reactive, non-volatile medium bath can be heated to the desired treatment temperature before immersion of the printed parts, ensuring rapid and uniform heating. The inert nature of silicone oil, for example, can prevent unwanted chemical reactions with the polymer components while providing a stable thermal environment for the curing process. The viscosity of the non-reactive, non-volatile mediumcan be selected to provide adequate buoyancy support while allowing easy removal of the treated parts after the thermal processing is complete. In some embodiments, a non-reactive, non-volatile medium with a density lower than that of the printed object can be used, such that the printed object sinks but experiences lower-than-normal gravitational forces; it will be appreciated that for the purposes of the present disclosure, this can be referred to as “nearneutral buoyancy." In some embodiments, a non-reactive, non-volatile medium with a density higher than that of the printed object can be used, such that the printed object floats in the medium; it will be appreciated that for the purposes of the present disclosure, this can be referred to as “near-neutral buoyancy.”

[0067] The thermal curing mechanisms can result in the second solid, e.g., resin exposed to UV light at 365 nm, having a higher crosslink density and lower susceptibility7to swelling and dissolution when exposed to solvent than the first solid, e.g., resin exposed to visible light at 405 nm, after the heat treatment process. The increased crosslink density in UV-exposed regions can arise from the continued polymerization of epoxide monomers through cationic ring-opening mechanisms that are thermally driven or activated during the postprocessing treatment. The crosslinking reactions can create a three-dimensional network structure that restricts polymer chain mobility and reduces the ability of solvent molecules to penetrate and swell the polymer matrix. In some embodiments, the crosslink density can be quantified through dynamic mechanical analysis, where higher crosslink densities are evident through reduced tan delta peak heights and elevated glass transition temperatures. In some embodiments, the thermal treatment can increase epoxide conversion from approximately 50% immediately after UV exposure to over 90% after the heat treatment, resulting in a substantial increase in crosslink density and dissolution resistance.

[0068] The time duration of the thermal treatment can influence the extent of crosslinking reactions and the final dissolution properties of the treated materials. Shorter treatment times may result in incomplete crosslinking and intermediate dissolution resistance, while longer treatment times can maximize crosslink density and minimize solubility in the target solvents. The thermal treatment kinetics can follow first-order or second-order reaction mechanisms depending on the concentration of reactive species and the specific polymerization chemistry involved. In some embodiments, the thermal treatment can be performed using a temperature ramp profile where the temperature is gradually increased to the target value to minimize thermal shock and ensure uniform heating throughout the printed structures. The cooling rate after thermal treatment can also affect the final material properties, with controlled coolingpotentially influencing the crystallinity and morphology of the polymer networks. The thermal processing parameters can be optimized for specific applications by balancing the degree of crosslinking achieved against the processing time and energy requirements.

[0069] The thermal curing process can be monitored using various analytical techniques to ensure optimal processing conditions and consistent material properties. Differential scanning calorimetry' can be used to track the progress of polymerization reactions during thermal treatment by measuring the heat flow associated with crosslinking reactions. Fourier transform infrared spectroscopy can provide real-time monitoring of functional group consumption during thermal curing, allowing for precise control of the crosslinking process. In some embodiments, the thermal treatment can be performed in controlled atmosphere conditions to prevent oxidative degradation or other unwanted side reactions that might affect the final material properties. The thermal processing equipment can include temperature controllers, atmosphere control systems, and monitoring instrumentation to ensure reproducible processing conditions. The post-processing procedures can be integrated into automated manufacturing workflows where the thermal treatment parameters are controlled through programmable logic controllers or other process control systems.

[0070] The neutral or near-neutral buoyancy processing approach can be particularly beneficial for complex geometries or thin-walled structures that might be susceptible to deformation under their own weight during thermal treatment. The buoyancy forces provided by the non-reactive, non-volatile medium can counteract gravitational forces and maintain the structural integrity' of delicate features during the heating and cooling cycles. The thermal expansion coefficients of the non-reactive, non-volatile medium and the polymer materials can be matched to minimize differential expansion effects that might cause stress or distortion during temperature changes. In some embodiments, the bath can be agitated or circulated to ensure uniform temperature distribution and prevent the formation of thermal gradients that might lead to non-uniform curing. The selection of non-reactive, non-volatile fluids based on viscosity and density can be optimized based on the specific geometry and mass of the printed parts to achieve optimal buoyancy conditions. The neutral buoyancy approach can enable thermal processing of large or complex parts that would be difficult to support using conventional fixturing methods during high-temperature treatment.

[0071] SINGLE- WAVELENGTH PRINTING AND GRAYSCALE CONTROL

[0072] In some embodiments, the resin material 100 can achieve grayscale solubility control using single wavelength exposure with varying intensities, exposure times, or dosages to create continuous gradients in dissolution kinetics. That is, rather than having a second wavelength of light as in the multiwavelength material discussed above, the printing process can be performed using a single wav elength of light by changing an absolute intensity7of light, the grayscale patterned intensity of light, or the time of local light exposure. While it may be appreciated that in some embodiments, these three methods don't offer one-to-one correspondence with each other, in most cases they can be used interchangeably.Specifically, selective solubility or spatially varied solubility kinetics can be achieved using grayscale light exposure or varied exposure times for a single wavelength of light. The resin material can be at least one of iteratively or simultaneously exposed to different dosages of patterned light to spatially segregate at least one of a soluble region or an insoluble region.

[0073] For single-wavelength grayscale printing with a hybrid acrylate-epoxy resin, there exists a competition between time scales in which one chemistry is activated while a second chemistry' sits idle. Each reaction can have a degree of reactivity that depends on light intensity to which it is exposed. Photochemical processes can have different rate dependences on the intensity of incident light, where some reaction kinetics may scale linearly with light intensity, while others may scale with the square root of light intensity7, which is the case for free radical photopolymerization. Using photosensitizers such as methoxythioxanthone (MeOTX) in concert with iodonium photoinitiators, epoxide conversion can show different behavior at different wavelengths. In some embodiments, such as for 365 nm exposure, epoxide conversion can work as expected with a quick jump in conversion followed by a plateau. In some embodiments, for the 405 nm exposure, an inhibition period of approximately 75 seconds can occur with no epoxide conversion, but after this inhibition period, epoxide polymerization occurs and approaches the level reached by the 365 nm light exposure. This means that for short exposure times at 405 nm, acrylate polymerization can occur without any epoxide polymerization, and for long exposure times at 405 nm, both acrylate and epoxide polymerization occur, which leads to insolubility. It will be appreciated that the photosensitizer of the present embodiments is not limited to acting as a photosensitizer for the polymerization of acrylates or epoxides, and can act as a photosensitizer for one or more of an acrylate, epoxide, thiol, amine, or any compound that can be cross-linked.

[0074] Bridging monomers or bridging additives can serve as coupling agents that covalently link the thermoplastic and thermoset polymer networks formed during the dual polymerization processes. The bridging additives can contain both acrylate and epoxide functional groups, enabling participation in both free radical and cationic polymerization mechanisms. 3,4-epoxycyclohexylmethyl acry late (ECHA) can function as a representative bridging monomer, containing one acrylate group for free radical polymerization and one epoxide group for cationic polymerization. In some embodiments, the bridging monomer can include about 0.1% to about 25% of the resin composition, and act as a supporting method by which differential solubility is imparted, forming crosslinks between the first and second polymer networks. In some embodiments, the bridging monomer can comprise about 1% to about 50% of the resin composition, where the additional functional groups that are present on the bridging monomer can be the only such groups in the resin composition that are capable of undergoing a polymerization mechanism different from that of the monofunctional monomer, such that the bridging monomer or monomers impart selective solubility in the absence of other multifunctional monomers. It will be appreciated that the above-described features, as well as the below-described features, of the bridging monomer can also be applied to the multi-wavelength material and methods discussed above, such as those with respect to FIGS. 1 A-2E, and in the remainder of the present disclosure. In some embodiments, the bridging monomer can comprise 50-100% of the resin composition and act as the primary material imparting differential solubility. As a result, the bridging monomer can prevent dissolution of certain compounds when desired, with control of the dissolution occurring due to user preference.

[0075] In some embodiments, the bridging monomer can impart selective solubility in the absence of a second polymer network. In this embodiment, localized differences in crosslinking density can be mediated by side groups on the first polymer network type. For example, rather than using the second polymer network, the bridging monomer can impart selective solubility by curing the dangling epoxide chains thereof to form an insoluble thermoset material. When these dangling epoxide chains are not cured, the bridging monomer is simply incorporated into the backbone of the linear acrylate polymer that is formed, resulting in a soluble thermoplastic material.

[0076] When the bridging monomer constitutes a significant portion, e.g., about 1 wt% to about 50 wt% of the resin formulation, the material properties can be primarily determined by the relative extent of acrylate versus epoxide polymerization achieved through wavelength-selective light exposure. The dual functionality of bridging monomers can enable the formation of interpenetrating polymer networks where the thermoplastic and thermoset phases are covalently bonded rather than simply physically mixed. The molecular structure of the bridging monomer can influence the compatibility between the two polymer phases and the mechanical properties of the resulting composite material.

[0077] The bridging monomer approach can provide significant advantages for grayscale printing applications where precise control over dissolution kinetics is desired. In some embodiments, the spatial density of reaction additional functional groups of the bridging monomer can be varied throughout the resin formulation to create spatial gradients in crosslinking potential. This approach may enable the creation of materials with continuously variable dissolution rates across different regions of a single printed structure. The bridging monomer can act as a molecular switch that determines whether a given region will exhibit thermoplastic or thermoset behavior based on the local light exposure conditions. As noted above, the features of the bridging monomer discussed herein can also be applied to the multi-wavelength material and methods disclosed throughout the present disclosure.

[0078] For grayscale control applications, the bridging monomer can enable fine-tuned adjustment of material properties through controlled partial conversion of the reactive functional groups. In some cases, intermediate levels of epoxide conversion in the bridging monomer can result in materials with dissolution rates that fall between the fully soluble and fully insoluble extremes. This intermediate behavior may be particularly valuable for drug delivery applications where controlled release profiles are desired over extended time periods.

[0079] The bridging monomer can also facilitate the recycling process by providing a chemical pathway for the dissolution and recover)’ of support materials. When dissolved in monomer solvents, the bridging monomer components that have been reacted into the backbone of a linear polymer will retain their additional functionality, and these polymers can be recovered and reincorporated into fresh resin formulations without significant loss of performance of the functional pendant groups. This recycling capability may be enhanced when the bridging monomer comprises a substantial portion of the resin composition, as the recovered material can maintain the dual functionality necessary for wavelength-selective polymerization.

[0080] Photoinitiators and photosensitizers can enable wavelength-selective activation of the different polymerization mechanisms within the resin formulations. Free radical photoinitiators such as bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide (BAPO) can absorb light in the visible spectrum and generate free radicals that initiate acrylate polymerization. Photoacid generators such as triarylsulfonium hexafluoroantimonate salts can absorb UV light and generate strong acids that initiate cationic ring-opening polymerization of epoxide monomers. Photosensitizers can extend the wavelength range for polymerization initiation by absorbing longer wavelength light and transferring energy to photoinitiators through energy transfer or electron transfer mechanisms.Methoxy thioxanthone (MeOTX), isopropylthioxanthone (ITX). 2-ethyl-9,10-dimethoxyanthracene, anthracene, chlorophyll, camphorquinone, and 5,7-diiodo-3-butoxy-6-fluorone can function as photosensitizers for either ionic or free radical reaction mechanisms, enabling wavelength-selective curing at wavelengths up to 550 nm. The selection of photosensitizers can enable the use of longer wavelength light sources that may provide better penetration depth or reduced photodamage in biological applications. The concentration and combination of photoinitiators and photosensitizers can be optimized to achieve the desired polymerization kinetics and wavelength selectivity for specific applications.

[0081] Base quenchers can be incorporated into the resin formulations to control the extent of cationic polymerization and prevent excessive crosslinking in regions intended to remain dissolvable. The base quenchers can neutralize photogenerated or thermally generated acids and limit the propagation of cationic polymerization reactions during heat treatment or extended storage. Tertian amines such as triethylamine or diisopropylethylamine can function as base quenchers by protonating in the presence of strong acids, thereby consuming the acid catalyst and terminating cationic polymerization. Pyridine can serve as a base quencher with moderate basicity that can selectively neutralize strong acids while allowing weaker acids to remain active. Alcohols such as ethanol or isopropanol can act as chain transfer agents and base quenchers, participating in cationic polymerization reactions and reducing the molecular weight and crosslink density of the resulting polymers. Quaternary' ammonium salts, organic bases, and ammonium hydroxide can provide additional options for base quenching with different solubility and reactivity characteristics. The concentration of base quenchers can be maintained at molar amounts less than the photoinitiator concentrationto avoid complete inhibition of polymerization while providing controlled termination of crosslinking reactions.

[0082] Acid quenchers can be employed when using photobase generators for anionic polymerization mechanisms, where weak acids can be added in molar amounts less than the photobase generator concentration. The acid quenchers can neutralize photogenerated or thermally generated bases and control the extent of anionic polymerization in specific regions of the material. Carboxylic acids, phenolic compounds, and other weak acids can serve as acid quenchers that selectively neutralize strong bases while allowing controlled polymerization to proceed. The balance between photobase generators and acid quenchers can determine the spatial distribution of anionic polymerization and the resulting material properties. The selection of acid quenchers can be based on their pKa values, solubility7characteristics, and compatibility7with other resin components. The incorporation of acid quenchers can enable the use of photobase-initiated polymerization systems for creating materials with controlled dissolution properties. The concentration and reactivity of acid quenchers can be optimized to achieve the desired degree of polymerization control without completely inhibiting the intended polymerization reactions.

[0083] An alternative approach to achieving grayscale control can involve use of a photoinitiator that, under ordinary circumstances, allows immediate curing of epoxide, plus a base quencher which inhibits cationic polymerization until depleted that adds an inhibition period similar to that seen with MeOTX at 405 nm. The base quenchers can inhibit epoxide polymerization until depleted, at which point epoxide polymerization can continue uninterrupted. This could be done with 365 nm light in the existing system without a photosensitizer, plus a base quencher. Alternatively, it could be performed at 405 nm by adding a photosensitizer such as isopropylthioxanthone (ITX) which allows cationic polymerization to occur at 405 nm. Suitable base quenchers include tertiary amines such as triethylamine or diisopropylethylamine, pyridine, alcohols like ethanol or isopropanol, quaternary ammonium salts, organic bases, or ammonium hydroxide, ty pically in a molar concentration less than that of the cationic photoinitiator. It will be appreciated that the same method of attaining an inhibition period until an inhibiting agent is depleted upon continued exposure to light can be achieved for other polymerization mechanisms, allowing a temporal separation between separate polymerization mechanisms, and therefore a difference in solubility based on the dosage of light shown on any particular region. For instance, a free radical inhibitor would inhibit free radical polymerization until the amount of generated freeradicals is greater than the amount of inhibiting agent, or the polymerization rate is greater than the inhibition rate, at which point free radical polymerization would proceed. In some embodiments, the free radical inhibitor can have a molar concentration less than that of a free radical photoinitiator or photosensitizer in the system. Alternatively, an acid quencher can inhibit anionic polymerization until the amount of generated base is greater than the amount of acid quencher in the system, at which point any additional base generated can initiate anionic polymerization.

[0084] Single components of the system may serve multiple purposes. For instance, the free radical monomer may also act as an amine base quencher. One such example is the use of acrylamide-based monomers, such as N-isopropylacrylamide. Such components could contribute to both free radical polymerization, as well as base quenching for cationic polymerization. It is also possible that, at a separate wavelength between 405 nm and 460 nm, ITX in the absence of a base quencher may behave as MeOTX does at 405 nm, specifically showing a period of no epoxide polymerization, followed by epoxide polymerization after a defined inhibition period. Many other photosensitizers may work in a similar way, with even longer wavelengths possible, such as up to approximately 550 nm for 5,7-diiodo-3-butoxy-6-fluorone. The inhibition period may be tuned by changing the light wavelength, light intensity, photoinitiator concentration, photosensitizer concentration, base quencher identity, base quencher concentration, acid quencher identity, acid quencher concentration, free radical inhibitor identity, free radical inhibitor concentration, and more.

[0085] There are many other conceivable means for achieving single-wavelength printing of objects with gradients in solubility'. Inhibitors and quenchers provide a general way to achieve separation in reactivity between two simultaneous reactions by having a molecule that selectively inhibits the propagation of one polymerization reaction. These inhibitors are commonly used for stability and can slow down a polymerization reaction, usually by creating an induction zone. Common free radical inhibitors include MEHQ and DPPH. Common cationic inhibitors include base quenchers like pyridine, triethylamine, or diisopropylethylamine. If a photobase generator instead of a photoacid generator initiates ionic polymerization, then an acid quencher can be used for inhibition. Free radical polymerizations can be slowed dow n using a number of chemical functionalities, such as thiols and ynes. Competing reactions at an unequal stoichiometry or with different behavior at different light intensities can be used, such as the simultaneous use of a photoacid generator and photobase generator in one resin.

[0086] Gaseous inhibitor approaches can create selective reactions by flowing gaseous inhibitor molecules near the location of polymerization. For example, oxygen could be flowed to transiently introduce 02 molecules that inhibit radical reactions into the resin. This could be reversed by flowing N2 as an inert gas. Alternatively, an inhibitor for an ionic reaction, such as water or ammonia, may be flowed to get selectivity. This may involve the gas diffusing through a permeable membrane to get to the resin at the site of polymerization. Thermal initiation can use one photoinitiator and a thermal initiator. At high light intensities or long exposure times, either of the highly exothermic polymerization reactions generates a lot of heat, which in turn activates the thermal initiator, which can be cationic or free radical, triggering the second reaction that leads to local insolubility. Fast free radical curing with high light intensity leading to high heat generated could lead to the thermal initiation of a thermal cationic initiator and thus dual-polymer-network properties, whereas low light intensity would not generate heat fast enough to thermally initiate the cationic initiator, meaning that only a single network is formed and the region remains soluble.

[0087] A similar approach involves using heat-sensitized nano-capsules or micro-capsules that release an initiating or co-initiating species in response to temperature or light exposure. High light intensities lead to faster polymerization and lots of generated heat, and above a certain temperature, the capsules can burst open or otherwise release catalyzing or initiating species that promote a secondary polymerization reaction. Light intensity variations can be used with the existing chemistry, where high light intensities or exposure times lead to higher epoxide conversions, but for low light intensities or exposure times, partially reacted epoxides are formed. High epoxide conversions are insoluble, but low epoxide conversions can remain soluble until they reach a desired epoxide conversion or crosslinking density. This way, grayscale-controlled solubility' can be achieved without requiring additional additives or techniques. Free radical and cationic polymerization kinetics scale differently with light intensity, where low intensity and high intensity lead to different relative differences in conversion as a function of total energy input from light exposure, which could help in selectively curing soluble and insoluble regions.

[0088] Light absorption approaches can use a dye that heavily absorbs light in part of the spectrum where one of the two photoinitiations takes place, which would prevent it from occurring. After extended light exposure, the dye can be photobleached, thereafter allowing the light to penetrate deeper into the resin and activate the secondary photochemistry.Isomerization versus photobleaching can be employed where at low light intensities, it ispossible to isomerize certain molecules like spiropyran into an active form such as merocyanine that can do certain chemistry to initiate or inhibit a reaction. At high light intensities, photobleaching processes can permanently degrade the molecule, changing the active chemistries. At certain wavelengths, some photoinitiators are orders of magnitude more highly absorbing than others. This could be taken advantage of, using either the variable cure depth, or the fact that the photoinitiators themselves may be able to be photobleached after enough light exposure.

[0089] Other chemistries can provide alternative routes for achieving differential solubili ty. For example, photo-ROMP and photo-hydrosilylation could be used. Early work with vat photopolymerization using photo-activated ring-opening metathesis polymerization (ROMP) has shown that low light intensity7can lead to a semicrystalline, insoluble polymeric solid, while higher light intensities lead to an amorphous, soluble polymeric solid, allowing differential solubility using grayscale light. There are many other possible reaction pathways such as thiol-ene, Michael addition, click reactions, and more that could potentially lead to differential solubility . Multi-stage initiation can combine two different classes of initiators with different reactivities. One initiator could involve a bimolecular reaction such as photosensitizer plus initiator versus a second initiator that reacts by itself without needing an additional molecule. The addition of co-initiating molecules or photosensitizers can either significantly increase or decrease the rate of initiation and thus polymerization kinetics, which could be used to favor one polymerization reaction over another at different timescales or light intensities.

[0090] Drug release applications can benefit from gradient dissolution behavior for biomedical applications, which are also discussed in greater detail below. For example, combining the selective solubility concept with grayscale control of light intensity can lead to complete spatial control of dissolution kinetics. With or without heat treatment, the amount of UV light exposed locally leads to vary ing local degrees of cure and thus vary ing local dissolution rates. This could have massive implications for drug delivery and pharmaceuticals. It has already been shown with this material that some compounds, such as dye, are only7released into solution when the surrounding material has been fully7dissolved. Therefore, intermediate levels of monomer conversion can allow for tailored drug and matrix dissolution profiles, with full control over both the geometry and the spatial variation of dissolution kinetics. As an example, ingested or implanted drug release devices could have tailored drug release profiles, for instance, a quick spike in drug release over a few minutes,followed by several weeks of slow drug release to maintain consistent levels of bioavailable drugs for a wide variety of diseases. This technique can also be used outside human medicine, such as to have a spatially tailored release of compounds for problems such as industrial water treatment, aquarium health, catalyst release, or large-scale synthesis.

[0091] Other applications of selective solubility material extend beyond 3D printing supports. This material can be used for long-term drug release devices, structural or tissue implants that release anti-inflammatories over time, and more. Many additional possibilities can be realized. For instance, this material could be used as nail polish that can be patterned with light, then the soluble portion washed away to create textured or multi-layered designs. This material could also be used for coatings, with sacrificial regions etched away to make room for some other coating such as paint. Conceivably, this material could also be used for photolithography, MEMS fabrication, or other lithography -like processes. The singlewavelength approach can simplify the optical systems required for multi-material printing while maintaining the ability to create complex dissolution behaviors through intensity7and exposure time control, enabling the fabrication of structures with integrated support materials or controlled release features.

[0092] FIGS. 3A-3F illustrates demonstration prints that showcase the capabilities of the wavelength-selective photopolymerization process for creating complex geometries that would be challenging or impossible to achieve with conventional vat photopolymerization methods. FIGS. 3A-3C show a print-in-place assembly 200 featuring three separate structures, including two meshed gears 202 connected by an axle 204, wi th the gears 202 capable of rotating in sync with each other after support dissolution. The gear assembly 200 demonstrates the ability to print functional mechanical components with moving parts that are pre-assembled during the printing process, eliminating the need for post-assembly operations. The gears 202 maintain proper meshing and clearances after the dissolvable support material 206 is removed, enabling immediate functionality upon completion of the dissolution process.

[0093] FIGS. 3D-3F show additional lattice configurations that demonstrate the versatility of the wavelength-selective approach for creating structures with varying geometric complexity and support requirements. These structures include overhanging elements, bridging features, and enclosed volumes that benefit from the automated support removal capabilities enabled by the selective dissolution process. For example, FIG. 3D illustrates a gyroid lattice structure 210 with complex internal channels and a reentrant lattice structure220 featuring auxetic metamaterial properties with negative Poisson's ratio characteristics. The gyroid geometry 210 presents a challenging test case for support removal due to its intricate three-dimensional network of interconnected channels and surfaces. The wavelength-selective approach can enable dissolution of support material 226 from within the complex internal geometry, including thin channels and enclosed volumes that would be inaccessible for manual support removal. The resulting structure can maintain its intended geometric properties and structural integrity after the support dissolution process. The reentrant geometry 220 can include inward-pointing features that create mechanical properties not achievable with conventional materials. The complex geometry can utilize support structures during printing to maintain the precise angular relationships and dimensional accuracy demanded for the auxetic behavior. The dissolvable support approach can enable the fabrication of these intricate geometries without compromising the delicate structural features that provide the unique mechanical properties.

[0094] FIGS. 3G-3I illustrate volumetric packing arrangements that maximize build volume utilization while enabling efficient material recycling through the dissolution of support structures. FIG. 3G shows a three-dimensional array of cylindrical objects 230 arranged in a stacked configuration that can optimize the use of available build volume. The arrangement can enable the simultaneous production of multiple identical parts within a single printing operation, significantly increasing manufacturing throughput compared to conventional approaches that require individual part orientation and spacing considerations.

[0095] FIG. 3H illustrates the support structure design that facilitates solvent access during the dissolution process while providing adequate mechanical support during printing. The support material 236 can include channels and void spaces 238 that can reduce the total amount of resin used while enabling rapid penetration of dissolution solvents throughout the support structure. The channel design can accelerate the dissolution process by providing multiple pathways for solvent flow and dissolved material removal to produce the buttons shown in FIG. 31 and the inset (i).

[0096] FIGS. 3J-3L illustrate a printed denture base 242 and assembled denture model 240. For this print, a thin interface between the supports and the object can be printed with soluble material. This allows for fast and automatable support removal in a solvent. The teeth inserts can be printed with a commercial resin in a separate DLP printer, with 1 : 1 size scaling. FIGS. 3J-3L illustrate the progression of the dissolution process, demonstrating how the support structures are systematically removed to reveal the individual printedcomponents. While the volumetric packing approach can enable the recovery' of support material from multiple parts simultaneously, creating economies of scale that improve the overall efficiency of the material recovery operation, the dissolved support material can be processed through the recycling pathway to create new resin formulations for subsequent printing operations, reducing material waste and improving the sustainability of the manufacturing process.

[0097] The use of the dissolvable support interfaces of FIGS. 3I-3L can be further observed in FIGS. 4A-4G. As shown, a dissolvable interface between the part and traditional VP support can allow for fast support removal time compared to the full dissolution of an enclosing shell of dissolvable material. This strategy can make full support removal possible in less time than would be needed to remove supports from a part fully encased or supported by dissolvable material. FIGS. 4A-4D and 4E-4G illustrate two denture base prints 240, 340 with different support geometries 242. 342, each having a soluble interface between the support and the object. This allows for rapid, automatable separation of the part from its supports by dissolving (or melting) the support interfaces away.

[0098] DRUG DELIVERY

[0099] In some embodiments, the resin material 100 can be used in drug delivery applications where spatial control of degradation kinetics can enable tailored drug release profiles. For example, the resin material 100 can incorporate drugs that are chemically or physically bonded to resin components, where the polymer itself may be the drug, contain the drug, or have the drug bonded to the polymer for controlled release applications. The composition for use in drug delivery' can comprise one or more monomers and one or more of photoinitiators or photosensitizers that are capable of photocuring using a first polymerization mechanism at a first wavelength, and one or more monomers and one or more of photoinitiators or photosensitizers that are capable of photocuring using a second polymerization mechanism at a second wavelength, where the second polymerization mechanism may be different than the first polymerization mechanism.

[0100] For use in drug delivery applications, the resin material 100 can produce a first solid that may be capable of degradation in a plurality' of solvents after the resin material is exposed to light at a first wavelength, and the resin material can produce a second solid that has different degradation behavior in the plurality of solvents after the resin material is exposed to light at a second wavelength. These solids can be arranged in a core-shellconfigurations that provide variable degradation rates for pharmaceutical applications where different drug release profiles may be desired. FIGS. 5A-5B. for example, show an example embodiment of a drug core-shell structure 400 that includes a central core region 402 and an outer shell region 404, with each region designed to exhibit different degradation properties based on the wavelength of light exposure during fabrication. The degradation behavior of the core-shell structure 400 can vary over time, showing distinct phases of material degradation that correspond to the different regions of the device. For example, the shell region 404 may be configured to degrade rapidly to provide an initial burst release of therapeutic compounds, while the core region 402 may be configured to degrade more slowly to provide sustained release over an extended period. The degradation curve shown in FIG.5C demonstrates how different regions of a drug delivery device can exhibit distinct degradation profiles, with the shell region 404 dissolving rapidly within the first 30 minutes followed by the core region 402 that degrades more gradually over an extended time period. As shown, the gradual release of drugs can be tailored to ensure that consistent levels of bioavailable drugs in a body of a patient are maintained. It will be appreciated that the values for the first and second wavelengths illustrated in FIG. 5C are merely exemplary and can be varied, which would likely later the degradation kinetics of the drug core-shell structure 400. For purposes of the present disclosure, degradation can refer to selective degradability7of the central core region 402 and the shell region 404, which includes both a chemical and a physical process. In particular, the selective degradability7of the core-shell structure 400 can refer to the chemical breaking of bonds, e.g, covalent bonds in the core-shell structure 400, followed by physical dissolution of the materials therein to provide the desired release effects. It will be appreciated that in some embodiments of the scope of the present disclosure, one of the core region 402 and / or the shell region 404 of the core-shell structure 400 can degrade while the other dissolves.[01011 The drug delivery devices can be designed with channels or porous structures that facilitate fluid penetration and drug diffusion while maintaining structural integrity7during the degradation process. The geometric design of the drug delivery device can influence the surface area available for degradation and can be used to control the overall release kinetics. Complex internal geometries can be created through the multi-wavelength photopolymerization process to provide tortuous diffusion paths that further modulate drug release rates. The relative thicknesses of the shell and core regions can be adjusted to tailor the duration and magnitude of each release phase.

[0102] The spatial segregation of soluble and insoluble regions can occur in the resin material when the resin material is at least one of iteratively exposed to light at the first wavelength and light at the second wavelength or simultaneously exposed to light at the first wavelength and light at the second wavelength, where the light at the first wavelength and the light at the second wavelength may be patterned to define the spatially segregated regions. The solubility of a region of the photocured resin material in a plurality of solvents can be based on at least one of light intensity or time of light exposure of the region to at least one of the first wavelength of light or the second wavelength of light, with a sol ubility of a second region being different than that of the first region. The resin three-dimensional printing can be used to create three-dimensional structures having the soluble and insoluble regions that enable controlled drug release applications. The spatial control of the light dosage of the resin material can enable control over the local degree of solubility or degradation kinetics of the material, ranging from a maximum rate of solubility along a range of degradation rates that extend down to zero, at which point the material may be fully insoluble. The solubility7of the resin material can be configured to be tuned by adjusting a location of a light intensity along the resin material, where the solubility can be configured to be tuned in one or more regions of the resin material.

[0103] With continued reference to FIGS. 5A-5C, a continuous or discrete gradient in spatial solubility can be formed as a result of time-variant intensity of patterned light exposure during the photopolymerization process. The drug delivery composition can further comprise an additive that includes one or more monomers which have two or more separate chemical groups that are capable of covalently crosslinking polymers formed by the one or more monofunctional monomers and the one or more multifunctional monomers. The polymers that comprise the drug delivery7system can have non-covalent interactions that change the solubility of the resulting material, where the non-covalent interactions can include, but are not limited to. at least one of hydrogen bonding, hydrophobic interactions, electrostatic interactions, ionic bonding, pi-pi-stacking, or polymer entanglement. These non-covalent interactions can provide additional mechanisms for controlling drug release kinetics beyond the covalent crosslinking achieved through the photopolymerization processes. The solubility of the resin material can be localized to specific regions, enabling the creation of drug delivery devices with precisely controlled release zones.

[0104] The drug delivery device can be fabricated with precise geometric control over the core 402 and shell regions 404 through the use of patterned light exposure during thephotopolymerization process. The core region 402 may be exposed to light conditions that promote extensive crosslinking and slower degradation, while the shell region 404 may be exposed to light conditions that result in less crosslinking and more rapid degradation. The interface between the core and shell regions 402, 404 can be designed to provide either a smooth transition in degradation properties or a sharp boundary depending on the desired release characteristics.

[0105] In some embodiments, different drugs can be incorporated into the core and shell regions to provide combination therapy with tailored release profiles for each therapeutic agent. The polymer matrix can be designed to protect sensitive drug molecules from degradation while providing controlled release upon degradation. The drug loading capacity of different regions can be varied by adjusting the polymer network density and the incorporation of drug-binding functional groups. The degradation behavior of the drug delivery device can be designed to respond to specific biological environments, such as the acidic conditions in the stomach or the neutral pH conditions in the intestine.

[0106] In some embodiments, multiple shell layers with different degradation rates can be incorporated to create more complex release profiles with multiple phases of drug release. The drug molecules can be distributed uniformly throughout the polymer matrix or can be concentrated in specific regions to further customize the release profile. The polymer networks formed in different regions can be designed to respond to specific physiological conditions such as pH changes, temperature variations, or the presence of specific enzymes that may trigger drug release. The spatial arrangement of the core and shell regions can be optimized based on the specific therapeutic application and the desired pharmacokinetic profile.

[0107] RECYCLING

[0108] Referring to FIG. 6 (I)-(IV), the resin material 100 can be recycled through a monomer-based recycling process that enables the dissolution and reprocessing of support structures into new resin batches. The recycling process can begin with printed objects 500, as shown in (II), that contain dissolvable support structures 502 formed through the wavelength-selective or dosage-selective photopolymerization process, e.g., via printing and heating in step SI. The support structures 502 can be dissolved in monomer components 504 rather than inert solvents, as in step S2, which can allow for the recovery and reuse of the polymer material in subsequent printing operations. The monomer components 504 caninclude isobomyl acrylate (IBOA) to dissolve the support material 502. creating a solution that contains dissolved polymer along with the original monomer. In some embodiments, elevated temperatures, mixing, ultrasonication, or other agitation methods may be used during the dissolution process. In some embodiments, the dissolution rate in resin at the temperature used during printing can be slow or negligible relative to the speed at which the part is printed, such that the support material does not appreciably dissolve during the printing process. The finished product 506 can then be extracted from the solution in step S3. The recycling pathway shown in FIG. 6 demonstrates how the dissolved material can be reintroduced into the resin formulation process, creating a closed-loop system that reduces material waste. In some embodiments, the resin material 100 can progress through printing, heat treatment, dissolution, and extraction steps before being reprocessed into fresh resin for additional printing cycles. In some embodiments, the printed material does not undergo heat treatment prior to recycling taking place.

[0109] The monomer-based dissolution approach can provide several advantages over the use of inert solvents, including the ability to recover and reuse the dissolved polymer material. In some embodiments, the monofunctional monomers such as isobomyl acrylate can serve as either of the polymerizable components in the original resin formulation and the dissolution medium for the recycling process. In some embodiments, the resin itself, or any combination of resin components, can be used as the solvent in w hich the printed materials are dissolved. The dissolved polymer can remain chemically compatible with the monomer or resin component solvent, creating a homogeneous solution that can be directly incorporated into new resin batches. The monomer-based dissolution process can eliminate the need for polymer precipitation and purification steps that would be required when using inert solvents. The recycling efficiency can be enhanced by selecting monomers or resin components that provide good solvation properties for the target polymer while maintaining stability during storage and handling.

[0110] In some embodiments, the monomer-based dissolution process can achieve up to 75% mass recovery of the original support material for reuse in subsequent resin batches. In principle, 100% mass recover}' of the original support material can be possible w ith finely tuned chemistry and recycling processes. In some embodiments, the dissolved support material can be processed through filtration and centrifugation steps to remove any residual solid particles and create a solution suitable for reuse in resin formulations. The recycled monomer solution can contain dissolved poly(IBOA) and other polymer components thatwere originally present in the support structures. In some embodiments, the recycled solution can be used to replace up to 15% by weight of the fresh monomer in new resin batches without affecting the printing quality or mechanical properties of the resulting printed parts. The recycling process can be repeated multiple times, with each cycle recovering a substantial portion of the support material for reuse. The sustainability benefits of this recycling approach can include reduced material waste, lower raw material consumption, and decreased environmental impact compared to traditional additive manufacturing processes that generate non-recyclable support waste.

[0111] With continued reference to FIG. 6, the monomer solution 504 prior to the extraction step S3 can produce both finished parts and recycled material that can be incorporated into fresh resin formulations. In some embodiments, the recycled material can maintain the same chemical composition and polymerization behavior as the original monomer components, allowing for seamless integration into new resin batches. In some embodiments, the recycled resin formulation may be modified compared to the original formulation in order to enhance the printability, dissolution, or other characteristics of the dissolved polymer-containing resin. The recycling process can be optimized by controlling the dissolution temperature, dissolution time, and solvent-to-polymer ratio to maximize the recovery efficiency. In some embodiments, the dissolution can be performed at elevated temperatures to accelerate the dissolution kinetics and improve the recovery yield. The recycled polymer solution can be characterized using spectroscopic techniques to verify the chemical composition and ensure compatibility with fresh resin components. In some embodiments, the mechanical properties of parts printed with recycled resin can remain substantially unchanged compared to parts printed with virgin resin, demonstrating the effectiveness of the recycling process in maintaining material performance. The recycling process of the present embodiments can recover the support material from multiple parts simultaneously, creating economies of scale that improve the overall efficiency of the material recovery operation. The sustainability benefits of the volumetric packing and recycling approach can include reduced material waste, improved resource utilization, and lower manufacturing costs compared to traditional additive manufacturing processes.

[0112] The recycling process can be integrated into automated manufacturing workflows where the dissolution and material recovery operations are performed without manual intervention. The recycled resin that formed the supports can be formulated to match the properties of virgin resin through the addition of fresh monomers, photoinitiators, and otheradditives as needed. The quality control procedures can include testing of the recycled resin to verify polymerization kinetics, mechanical properties, and printing performance before use in production operations. In some embodiments, the recycling process can be performed onsite at manufacturing facilities, reducing transportation costs and enabling rapid turnaround of recycled materials. The monomer-based recycling approach can be applied to various types of support structures and part geometries, providing flexibility in manufacturing operations. The environmental benefits of the recycling process can include reduced landfill waste, lower carbon footprint, and conservation of raw materials compared to conventional manufacturing approaches that do not incorporate material recovery systems.

[0113] CHEMICAL COMPOSITION

[0114] The chemical composition of the resin materials can comprise various monofunctional monomers that sen e as the primary components for forming dissolvable thermoplastic regions upon photopolymerization. The monofunctional acry late monomers can include isobomyl acrylate (IBOA), ethylene glycol phenyl ether acrylate, 4-acryloylmorpholine, or combinations thereof. In some embodiments, isobomyl acrylate may constitute approximately 60 wt% of the total resin composition, providing the bulk material that forms the dissolvable polymer networks. The bulky' isobomyl side group in IBOA can contribute to the mechanical stability’ of the resulting thermoplastic while maintaining solubility in various organic solvents. The high glass transition temperature of poly(IBOA) can enable the formation of rigid thermoplastic materials that maintain structural integrity during printing operations while remaining dissolvable in post-processing solvents. The monofunctional nature of these monomers can result in linear or branched polymer chains without crosslinking, which facilitates dissolution in appropriate solvent systems.

[0115] The resin formulations can incorporate water-soluble monomers to enable dissolution in aqueous environments for specific applications. Water-soluble monofunctional monomers can include poly(ethylene glycol) based monomers, 4-acryloyl morpholine, 2-hydroxy ethyl acrylate, 2-hydroxyethyl methacrylate, acrylic acid, acrylamide, and N-isopropylacrylamide. These hydrophilic monomers can undergo free radical polymerization to produce water-soluble polymers that dissolve readily in aqueous solutions. The incorporation of poly(ethylene glycol) based monomers can provide biocompatibility and controlled syvelling behavior in biological fluids. Acrylamide-based monomers such as N-isopropylacrylamide can exhibit temperature-responsive dissolution behavior, where the solubility changes dramatically with temperature variations. The acrylic acid monomer canintroduce carboxylic acid functional groups that respond to pH changes, enabling pH-triggered dissolution in biological or environmental applications. The selection of water-soluble monomers can be tailored based on the specific dissolution requirements and environmental conditions where the materials will be used.

[0116] The multifunctional monomers in the resin compositions can comprise difunctional or multifunctional epoxide crosslinkers that form the insoluble thermoset regions upon cationic ring-opening polymerization. In some embodiments, difunctional epoxide crosslinkers can constitute approximately 40 wt% of the total resin composition, providing the reactive species that form crosslinked networks resistant to dissolution. Common epoxide crosslinkers can include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate (EPOX), bisphenol A diglycidyl ether, and other cycloaliphatic or aromatic epoxide compounds. The ring strain in the epoxide functional groups can facilitate ring-opening polymerization under cationic conditions, leading to the formation of ether linkages and crosslinked netw ork structures. The multifunctional nature of these crosslinkers can create three-dimensional polymer networks with high crosslink density and reduced chain mobility. The crosslinked thermoset networks can exhibit enhanced mechanical properties, thermal stability, and resistance to swelling and dissolution in organic solvents. The ratio of difunctional to multifunctional epoxide crosslinkers can be adjusted to control the crosslink density7and the resulting dissolution resistance of the cured material.

[0117] The solvent systems used for dissolving the photopolymerized materials can include various organic solvents and aqueous solutions depending on the chemical composition of the polymer networks. Organic solvents such as mineral oil, D-limonene, ethyl acetate, mineral spirits, turpentine, paint thinner, and toluene can dissolve thermoplastic regions formed through free radical polymerization of acrylate monomers. Water-based solvents can be used for dissolving materials formed from water-soluble monomers, enabling environmentally friendly dissolution processes. The selection of dissolution solvents can be based on the chemical compatibility with the target polymer, the dissolution kinetics required for the application, and safety considerations for handling and disposal. Mineral oil can provide a safe, non-toxic dissolution medium that may be suitable for biomedical applications or consumer products. D-limonene can offer a bio-based solvent option w ith pleasant odor characteristics and reduced environmental impact compared to petroleum-based solvents. The dissolution rate can be controlled through solvent selection, temperature, agitation, and the addition of co-solvents or dissolution enhancers.

[0118] Non-covalent interactions can play a role in determining the solubility characteristics of the polymers formed in both the soluble and insoluble regions of the photopolymerized materials. Hydrogen bonding interactions can occur between polymer chains containing hydroxyl, carboxyl, amide, or other hydrogen bond donor and acceptor groups. Hydrophobic interactions can influence the solubility' of polymers in aqueous environments, where hydrophobic polymer segments tend to aggregate and reduce water solubility. Electrostatic interactions can occur between charged polymer segments, particularly in materials containing ionic functional groups or ionizable groups that respond to pH changes. Ionic bonding can form between oppositely charged polymer chains or between polymer chains and ionic additives, creating physical crosslinks that affect dissolution behavior. Pi-pi stacking interactions can occur between aromatic groups in the polymer structure, contributing to intermolecular associations that influence solubility and mechanical properties. Polymer entanglement can create physical constraints on chain mobility' that affect dissolution kinetics, particularly in high molecular weight polymers or densely packed polymer networks. The combination of these non-covalent interactions can be tailored through monomer selection and polymer architecture to achieve the desired dissolution characteristics.

[0119] The regions that remain soluble after photopolymerization can be devoid of heavily crosslinked constituents, including primarily linear or branched polymer chains that can be dissolved through solvation and chain disentanglement processes. The absence of covalent crosslinks in the soluble regions can enable polymer chains to be separated and dissolved when exposed to appropriate solvents. The molecular weight and molecular weight distribution of the linear polymers can influence the dissolution rate, with lower molecular weight polymers generally dissolving more rapidly than higher molecular weight polymers. The polymer chain architecture can affect the dissolution behavior, where branched polymers may exhibit different dissolution kinetics compared to linear polymers of similar molecular weight. The glass transition temperature of the linear polymers can influence the dissolution process, where polymers with lower glass transition temperatures may exhibit faster dissolution due to increased chain mobility'. The chemical composition of the polymer backbone and side chains can determine the solvent compatibility and dissolution thermodynamics. The crystallinity of the polymer can affect dissolution behavior, where amorphous regions typically dissolve more readily than crystalline regions due to the lower energy barrier for solvation.

[0120] The resin formulations can incorporate additional monofunctional monomers beyond those previously described to expand the range of dissolution properties and application possibilities. Ethylene glycol phenyl ether acrylate can serve as a monofunctional acrylate monomer that provides enhanced compatibility with aromatic solvents and may offer improved mechanical properties in the resulting thermoplastic regions. Additional monofunctional acrylate options can include phenoxy ethyl acrylate (PEA), phenol (4EO) acrylate, o-phenylphenoxyethyl acrylate (OPPEOA), cyclic trimethylpropane formal acrylate (CTFA), tetrahydrofuryl acrylate, 2-(2-ethoxyethoxyl) ethyl acrylate (EOEOEA), octyl decyl acrylate (ODA), isodecyl acrylate (IDA), laur l acrylate (LA), and tripropyleneglycol monomethyl ethyl acry late (TPGMEMA). These monomers can provide varying degrees of flexibility, hydrophobicity, and dissolution characteristics in the final thermoplastic regions.

[0121] Multifunctional acrylate crosslinkers can be incorporated to create alternative crosslinking mechanisms or hybnd network structures. Hexanediol diacrylate (HDDA). bisphenol-A (4EO) diacrylate, polyethyleneglycol diacrylates with varying molecular weights (PEG200DA, PEG300DA, PEG400DA, PEG600DA), tripropyleneglycol diaciylate (TPGDA), 3-methyl-l,5-pentanediol diacrylate (MPDDA), neopentylglycol (2PO) diaciy late (NPGPODA), dipropyleneglycol diacrylate (DPGDA), hexanediol (2EO) diacrylate (HD2EODA), and hexanediol (2PO) diacrylate (HD2PODA) can function as difunctional crosslinkers. Higher functionality7crosslinkers can include trimethylolpropane triacrylate (TMPTA), trimethylolpropane (3PO) triacrylate (TMP3POTA), glycery l (4PO) triacry late (GPTA), trimethylpropane (3EO) triacrylate (TMP3EOTA), trimethylpropane (9EO) triacrylate (TMP9EOTA). trimethylpropane (15EO) triacrylate (TMP15EOTA), tris(2-hydroxy ethyl) isocyanurate triacrylate (THEICTA), pentaerythriol tri and tetraacrylate, pentaery thritol (5EO) tetraacrylate (PPTTA), ditrimethylolpropane tetra-acry late (DiTMPTA). dipentaerythritol hexaacrylate (DPP A), and dipentaerythritol hexaacrylate (DPHA).

[0122] Specialized acrylate monomers can provide unique properties for specific applications. Acrylated epoxy soy oil (ESBOA) can offer bio-based content and flexibility7, while bisphenol A epoxy diacrylate can provide enhanced thermal stability7. Caprolactone acry late (CA) can contribute to biodegradability' and biocompatibility'. Cycloaliphatic acrylates such as 3,3,5-trimethyl cyclohexyl acrylate (TMCHA) and 4-tert-buty Icyclohexyl acrylate (TBCHA) can provide enhanced thermal stability and reduced shrinkage. Aromatic acrylates including benzyl acrylate (BZA) can offer improved mechanical properties andchemical resistance. Long-chain acrylates such as tridecyl acrylate (TDA), isodecyl acrylate (IDA), and stearyl acry late can provide flexibility and hydrophobic characteristics.

[0123] Additional epoxide monomers can expand the range of cationic polymerization options beyond the previously described compounds. Allyl glycyl ether, bis[4-glycidyloxy)phenyl]methane, 1 ,3-butadiene diepoxide, 1 ,4-butanediol diglycidyl ether, butyl glycyl ether, tert-butyl glycidyl ether, 1,2,5,6-diepoxycyclooctane, 1,2,7,8-diepoxyoctane, diglycidyl 1 ,2-cyclohexanedicarboxylate, N,N-diglycidyl-4-glycidyloxyaniline, 1,2-di epoxy butane, 3,4-epoxy-l -butene. 1,2-epoxy dodecane, 1.2-epoxyhexadecane, 1,2-epoxyhexane, l,2-epoxy-5-hexene, l,2-epoxy-2-methylpropane, exo-2,3-epoxynorbomane, 1,2-cyclooctane, 1,2-di epoxypentane, l,2-epoxy-3-phenoxypropane, (2,3-epoxypropyl) benzene, 1,2-epoxytetradecane, 2-ethylhexyl glycidyl ether, furfuryl glycidyl ether, glycerol diglycidyl ether, glycidyl hexadecyl ether, glycidyl isopropyl ether, glycidyl 4-methoxyphenyl ether, glycidyl 2-methylphenyl ether, isophorone oxide, 4,4'-methylenebis(N,N-diglycidylaniline), 2-methyl-2-vinyloxirane, neopentyl glycol diglycidyl ether, octyl glycidyl ether, decyl glycidyl ether, a-pinene oxide, propylene oxide, resorcinol diglycidyl ether, styrene oxide, tris(2,3-epoxypropyl) isocyanurate, tris(4-hydroxyphenyl)methyl triglycidyl. and 1,2-butylene oxide can provide varying reactivity, flexibility, and thermal properties in the crosslinked thermoset regions.

[0124] Oxetane monomers can offer alternative cationic polymerization mechanisms with different kinetics and properties compared to epoxide systems. 3-oxetanone, 3-bromooxetane, 3-iodooxetane, trimethylene oxide, 3 -hydroxy oxetane, 3-aminooxetane, 0-butyrolactone, oxetane-3-carboxylic acid, 3 -aminooxetane-3 -carboxylic acid, oxetane-3-methanol, 3-(aminomethyl) oxetane. 3-amino-3-methyloxetane, N-methyl-3-aminooxetane, 2-(3-oxetanylidene) acetonitrile, 3-methyl-3-oxetanecarboxaldehyde, 3-methyloxetane-3-carboxylic acid, 3-bromomethyl-3-methyloxetane, 3,3-dimethyloxetane, 3-methyl-3-oxetanemethanol, l-(3-methyloxetan-3-yl)methanamine, 3-ethyl-3-oxetanemethanol. and 3-(phenoxymethyl)-3-oxetanylamine can provide rapid cationic polymerization with reduced shrinkage compared to epoxide systems.

[0125] Bridging monomers with dual functionality can extend beyond ECHA to include various combinations of reactive groups. 4-Vinylbenzyl glycidyl ether, glycidyl vinyl ether, allyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, (3,4-epoxycyclohexyl)methyl methacrylate, 2-(vinyloxy)ethyl acrylate, 2-(vinyloxy)ethyl methacrylate, and 3-(acryloyloxymethyl)-3-methyloxetane can provide epoxide- vinyl or epoxide-acrylate dualfunctionality. Isocyanate-functional bridging monomers such as 2-isocyanatoethyl acrylate and 2-isocyanatoethyl methacrylate can enable urethane or urea linkage formation. Azide-functional monomers including 2-azidoethyl methacrylate and 3-azidopropyl methacrylate can participate in click chemistry reactions. Alkyne-functional monomers such as propargyl acrylate and propargyl methacrylate can enable copper-catalyzed azide-alkyne cycloaddition reactions. Silane-functional monomers including 3 -(trimethoxy silyl)propyl acrylate can provide inorganic-organic hybrid network formation. Additional bridging options can include 2-carboxyethyl acrylate, 2-(dimethylamino)ethyl acrylate, 2-bromoethyl acry late, 4-benzoylphenyl acrylate, 2-norbomyl methacry late, 2-norbomyl acrylate, and 2-mercaptoethyl methacrylate.

[0126] Radical scavengers can be incorporated to control polymerization kinetics and prevent unwanted crosslinking during storage or processing. Sorbitol, methylether hydroquinone, t-butylhydroquinone. hydroquinone. 2.5-di-t-butylhydroquinone, 2.6-di-tert-butyl-4-methyl phenol (BHT), 2,6-di-t-butyl-4-methoxy phenol, 2-tert-butyl-4-hydroxyanisole, 3-tert-butyl-4-hydroxyanisole, propyl ester 3,4,5-trihydroxy-benzoic acid, 2-(l,l-dimethylethyl)-l,4-benzenediol, diphenylpicrylhydrazyl, 4-tert-butylcatechol, N-methyl aniline, p-methoxy diphenylamine, diphenylamine. N,N'-diphenyl-p-phenylenediamine, p-hydroxydiphenylamine, phenol, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tetrakis(methylene(3,5-di-tert-butyl)-4-hydroxy-hydrocinnamate)methane, phenothiazines, alkylamidonoisoureas, thiodiethylene bis(3,5-di-tert-butyl-4-hydroxy -hydrocinnamate), l,2-bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyl)hydrazine. tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane. cyclic neopentanetetrayl bis(octadecyl phosphite), 4,4'-thiobis(6-tert-butyl-m-cresol), 2,2'-methylenebis(6-tert-butyl-p-cresol), and oxalyl bis(bcnzylidenchydrazide) can provide controlled inhibition of radical polymerization.

[0127] Nitroxide radical scavengers can offer reversible radical trapping capabilities. 2,2,6,6-tetramethyl-l-piperidinyloxy (TEMPO). 2,2,6,6-tetraethyl-l-piperidinyloxy, 2.2.6-trimethyl-6-ethyl-l-piperidinyloxy, 2,2,5,5-tetramethyl-l-pyrrolidinyloxy (PROXYL), dialkyl nitroxide radicals such as di-t-butyl nitroxide, diphenyl nitroxide, t-butyl-t-amyl nitroxide, 4,4-dimethyl-l-oxazolidinyloxy (DOXYL), 2,5-dimethyl-3,4-dicarboxylic-pyrrole, 2,5-dimethyl-3,4-diethylester-pyrrole, 2,3,4.5-tetraphenyl-pyrrole, 3-cyano-pyrroline-3-carbamoyl-pyrroline, 3-carboxylic-pyrroline, l,l,3,3-tetramethylisoindolin-2-yloxyl. 1, 1,3,3-tetraethylisoindolin-2-yloxyl, porphyrexide nitroxyl radicals such as 5-cyclohexylporphyrexide nitroxyl and 2,2,4,5,5-pentamethyl-A3-imidazoline-3-oxide-l-oxyl, galvinoxyl, l,3,3-trimethyl-2-azabicyclo[2,2,2]octane-5-oxide-2-oxide, and l-azabicyclo[3,3,l]nonane-2-oxide can provide controlled radical scavenging with potential for reversible activation.

[0128] Substituted variants of radical scavengers can offer enhanced solubility or reactivity characteristics. 4-hydroxy-TEMPO, 4-carboxy-TEMPO, 4-benzoxyloxy-TEMPO, 4-methoxy-TEMPO, 4-carboxylic-4-amino-TEMPO, 4-chloro-TEMPO, 4-hydroxylimine-TEMPO, 4-oxo-TEMPO, 4-oxo-TEMPO-ethylene ketal, 4-amino-TEMPO, 3-carboxyl-PROXYL, 3-carbamoyl-PROXYL, 2,2-dimethyl-4,5-cyclohexyl-PROXYL, 3-oxo-PROXYL, 3-hydroxylimine-PROXYL, 3-aminomethyl-PROXYL, 3-methoxy-PROXYL, 3-t-butyl-PROXYL, 3-maleimido-PROXYL, 3,4-di-t-butyl-PROXYL, 3'-carboxylic-PROXYL, 2-di-t-butyl-DOXYL, 5-decane-DOXYL, and 2-cyclohexane-DOXYL can provide tailored radical scavenging properties for specific applications.

[0129] Base quenchers can be expanded to include additional categories beyond those previously described. Basic N-heterocycles such as 4-dimethylaminopyridine, 4-pyrrolidinopyridine, 4-(diethylamino)pyridine, 2-methylpyridine, 3-picoline, 4-picoline, imidazole, 1 -methylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, benzimidazole, N-methylmorpholine, N-ethylmorpholine, and N-methylpiperidine can provide varying degrees of basicity and solubility characteristics. Cyclic amidines and guanidines including l,8-diazabicyclo[5.4.0]undec-7-ene. l,5-diazabicyclo[4.3.0]non-5-ene. l,5,7-triazabicyclo[4.4.0]dec-5-ene, and 1,1,3,3-tetramethylguanidine can offer strong base quenching capabilities.

[0130] Tertiary' aliphatic amines can include tri-n-propylamine, tri-n-butylamine, triisobutylamine, trihexylamine, trioctylamine, N,N-diisopropylmethylamine, N,N-diisopropylethylamine, andN,N-diisopropylpropylamine. Hindered non-nucleophilic amines such as 2,6-diisopropylpyridine. 2,6-diethylpyridine, 2.6-lutidine. 2,4,6-colhdine, 1,8-bis(dimethylamino)naphthalene, quinuclidine, and l,4-diazabicyclo[2.2.2]octane can provide base quenching with reduced nucleophilicity. Amino alcohols and alkanolamines including triethanolamine, diethanolamine, monoethanolamine, N,N-dimethylethanolamine, 2-dimethylamino-2-methyl- 1 -propanol, 2-amino-2-methyl- 1 -propanol, 2-(diisopropylamino)ethanol, and tris(hydroxymethyl)aminomethane can offer base quenching with additional hydrogen bonding capabilities.

[0131] Phosphazene and proazaphosphatrane superbases such as t-Bu-P4, P2-Et, P2-t-Bu, Pl-t-Bu, BEMP, and proazaphosphatrane can provide extremely strong base quenching for highly acidic systems. Dialkyl sulfides and thioethers including diethyl sulfide, di-n-propyl sulfide, di-n-butyl sulfide, diisopropyl sulfide, thioanisole, diphenyl sulfide, and thiodiglycol can offer alternative base quenching mechanisms. Tertiary phosphines such as triphenylphosphine, tri-n-butylphosphine, trioctylphosphine, tris(2,4,6-trimethoxyphenyl)phosphine, tricyclohexylphosphine, and hexamethylphosphoramide can provide strong nucleophilic base quenching.

[0132] Polymeric bases and resin-bound quenchers including poly(4-vinylpyridine), poly(ethyleneimine), poly(N,N-dimethylaminoethyl methacrylate). poly(N-vinylimidazole), amine-functional acry lics, amine-functional polystyrenes, and basic ion-exchange resins in OH form can provide controlled release base quenching. Protic inhibitors and chain-transfer agents such as water, ethanol, i-propanol, n-butanol, benzyl alcohol, ethylene glycol. diethylene glycol, triethylene glycol, glycerol, sorbitol, pentaerythritol, and poly ether polyols can offer base quenching through proton donation.

[0133] Quaternary ammonium bases and salts with basic anions including tetramethylammonium hydroxide, tetra-n-but lammonium hy droxide, benzyltrimethylammonium hydroxide, tetraethylammonium acetate, tetraalkylammonium carbonate, tetraalkylammonium bicarbonate, and tetrabutylammonium fluoride can provide ionic base quenching mechanisms. Inorganic bases and basic fillers such as sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, calcium hydroxide, magnesium hydroxide, sodium carbonate, potassium carbonate, cesium carbonate, sodium bicarbonate, potassium bicarbonate, calcium carbonate, magnesium carbonate, basic oxides, basic alumina, and layered double hydroxides can offer solid-phase base quenching.

[0134] Base-quenching monomers can be incorporated to provide built-in base quenching functionality within the polymer network. Tertiary amine acrylates and methacrylates including 2-dimethylaminoethyl methacrylate, 2-diethylaminoethyl methacry late, 2-diisopropylaminoethyl methacrylate, 2-dimethylaminoethyl acrylate, N-(3-dimethylaminopropyl)acrylamide. N,N-dimethylaminopropyl methacrylamide. 2-morpholinoethyl methacrylate, and 2-morpholinoethyl acrylate can provide polymerizable base quenching functionality7. Vinyl N-heterocycles such as 4-vinylpyridine, 2-vinylpyridine, N-vinylimidazole, and N-allylimidazole can offer heterocyclic base functionality within the polymer backbone.

[0135] Oxazoline-bearing vinyl monomers such as 2-isopropenyl-2-oxazoline and triazole vinyl monomers including l-vinyl-l,2,4-triazole and 1 -vinyl-3 -amino- 1, 2, 4-triazole can provide additional base quenching mechanisms. Allylamines such as allylamine and diallylamine can offer primary and secondary amine base functionality. Amidine and guanidine-bearing monomers including methacryloyl guanidine, guanidinium-bearing methacrylamides, vinylbenzyl amidine derivatives, and vinylbenzyl guanidine derivatives can provide strong base functionality within the polymer structure.

[0136] Weakly basic amide and lactam monomers such as N-isopropylacrylamide. N-vinylpyrrolidone, and N-vinylcaprolactam can offer mild base quenching with additional hydrogen bonding capabilities. These monomers can provide controlled base quenching while contributing to the overall polymer network structure and properties.

[0137] Acid quenchers can be employed when using photobase generators for anionic polymerization mechanisms, where weak acids can be added in molar amounts less than the photobase generator concentration. The acid quenchers can neutralize photogenerated bases and control the extent of anionic polymerization in specific regions of the material.Carboxylic acids, phenolic compounds, and other weak acids can serve as acid quenchers that selectively neutralize strong bases while allowing controlled polymerization to proceed. The balance between photobase generators and acid quenchers can determine the spatial distribution of anionic polymerization and the resulting material properties. The selection of acid quenchers can be based on their pKa values, solubility characteristics, and compatibility with other resin components. The incorporation of acid quenchers can enable the use of photobase-initiated polymerization systems for creating materials with controlled dissolution properties. The concentration and reactivity of acid quenchers can be optimized to achieve the desired degree of polymerization control without completely inhibiting the intended polymerization reactions.

[0138] Acid-quenching monomers can be incorporated to provide built-in acid quenching functionality7within the polymer network that neutralizes or sequesters photobases and inhibits photobase generator-initiated or anionic processes. Carboxylic acid vinyl monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and 2-carboxy ethyl acrylate can provide polymerizable acid functionality that becomes incorporated into the polymer backbone. Dicarboxylic anhydride monomers such as maleic anhydride and itaconic anhydride can offer reactive acid functionality7that can undergo ringopening reactions with bases while participating in polymerization.

[0139] Strong protonic acids such as sulfuric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, nitric acid, perchloric acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, camphorsulfonic acid, trifluoromethanesulfonic acid, perfluorobutanesulfonic acid, perfluorosulfonic acid resins such as Nafion, trifluoroacetic acid, trichloroacetic acid, and difluoroacetic acid can provide strong acid quenching capabilities. Carboxylic and polycarboxylic acids such as acetic acid, propionic acid, butyric acid, benzoic acid, salicylic acid, phthalic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, itaconic acid, citric acid, tartaric acid, malic acid, acry lic acid, methacry lic acid, and crotonic acid can offer controlled acid quenching with varying strengths and solubility properties.

[0140] Polymeric acids such as polyacrylic acid, polymethacrylic acid, and polystyrenesulfonic acid can provide controlled release acid quenching mechanisms. Acid anhydrides and sultones such as acetic anhydride, maleic anhydride, succinic anhydride, phthalic anhydride, itaconic anhydride, phosphorus pentoxide, sulfur trioxide, antimony pentoxide, 1,3-propanesultone, and 1 ,4-butanesultone can offer reactive acid quenching species. Acid chlorides and sulfonyl chlorides including acetyl chloride, benzoyl chloride, acryloyl chloride, methacryloyl chloride, p-toluenesulfonyl chloride, methanesulfonyl chloride, and trifluoromethanesulfonic anhydride can provide strong electrophilic acid quenching mechanisms.

[0141] Lewis acids such as boron trifluoride diethyl etherate, boron trifluoride tetrahydrofuranate, boron trichloride, tris pentafluorophenyl borane, stannic chloride, titanium tetrachloride, aluminum trichloride, ferric chloride, zinc chloride, zirconium tetrachloride, antimony pentachloride, scandium triflate, and ytterbium triflate can provide alternative acid quenching mechanisms through coordination chemistry. Volatile acidic inhibitors such as sulfur dioxide, sulfur trioxide, nitric oxide, hydrogen fluoride, carbon dioxide, and hydrogen chloride can offer reversible acid quenching capabilities. Boronpolyol acid chelates such as boric acid plus ethylene glycol, boric acid plus glycerol, and boric acid plus sorbitol can provide controlled acid release mechanisms.

[0142] Ammonium and acid salts including ammonium chloride, ammonium bisulfate, ammonium dihydrogen phosphate, ammonium acetate, ammonium benzoate, ammonium citrate, and ammonium tartrate can offer buffered acid quenching systems. Acidic ionic liquids such as l-ethyl-3-methylimidazolium bisulfate can provide unique acid quenching properties with low volatility’ and high thermal stability. Phenolic acids and phenolicinhibitors such as phenol, cresols, p-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, hydroquinone, p-methoxyphenol, catechol, resorcinol, pyrogallol, gallic acid, tannic acid, bisphenol A, and tocopherols can offer mild acid quenching with antioxidant properties.[01431 Electrophilic base traps such as phenyl isocyanate, toluene diisocyanate, methylene diphenyl diisocyanate, hexamethylene diisocyanate, benzyl bromide, benzyl chloride, p-toluenesulfonyl fluoride, and vinyl sulfonyl fluoride can provide irreversible base neutralization mechanisms. Protic additives such as water, methanol, ethanol, i-propanol, and n-butanol can offer mild acid quenching through proton donation and can also serve as chain transfer agents in polymerization reactions.

[0144] Sulfonic acid monomers such as 2-acrylamido-2-methyl- 1 -propanesulfonic acid, vinylsulfonic acid, styrenesulfonic acid, and 3-sulfopropyl methacrylate in acid form can provide strong acid functionality within the polymer network. Phosphoric and phosphonic acid monomers such as vinylphosphonic acid, 2-hydroxyethyl methacrylate phosphate, and 10-methacryloyloxy decyl dihydrogen phosphate can offer phosphorus-based acid functionality with unique coordination properties. Phenolic vinyl monomers such as p-hydroxystyrene and 4-hydroxyphenyl acrylate can provide weak acid functionality with additional hydrogen bonding capabilities.

[0145] Electrophile-trap monomers such as 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl acrylate, acryloyl chloride, methacryloyl chloride, 4-vinylbenzenesulfonyl fluoride, and vinyl sulfonyl fluoride can provide reactive sites for irreversible base neutralization within the polymer matrix. Boron-acid vinyl monomers such as 4-vinylphenylboronic acid and vinylboronic acid pinacol esters can offer Lewis acid functionality that can coordinate with basic species while participating in polymerization reactions. These acid-quenching monomers can provide spatial control over base neutralization by incorporating the acid functionality directly into the polymer network structure, enabling localized control of anionic polymerization processes.

[0146] ADDITIONAL APPLICATIONS

[0147] The wavelength-selective photopolymerization materials disclosed herein may find application in various manufacturing processes beyond vat photopolymerization systems. Inkjet 3D printing processes may utilize these resin materials by depositing droplets of the photocurable formulation onto a substrate and selectively exposing different regions to specific wavelengths of light to create spatially controlled dissolution properties. The inkjetdeposition approach may enable the creation of complex multi-material structures where different regions exhibit varying solubility characteristics based on their light exposure history. Coating applications may benefit from the wavelength-selective properties by allowing the creation of coatings with regions that dissolve at different rates when exposed to specific solvents or environmental conditions. Casting processes may incorporate these resin materials to create molded parts with integrated dissolvable features that can be removed through selective dissolution after the casting operation is complete. The photocurable nature of these materials may make them compatible with any manufacturing process that utilizes light-activated polymerization mechanisms.

[0148] Coating applications may utilize the wavelength-selective dissolution properties to create functional surface treatments with controlled release characteristics. Industrial coatings may incorporate these materials to provide time-delayed release of lubrication agents, where the coating initially protects the underlying substrate and then dissolves to release lubricants when exposed to specific environmental conditions. Anti-clogging agents may be incorporated into coatings that dissolve in response to specific wavelengths of light or environmental triggers, releasing active compounds that prevent the accumulation of deposits or biological growth on surfaces. Biocidal agents may be embedded within coating matrices that undergo controlled dissolution to provide sustained antimicrobial activity over extended periods. The spatial control of dissolution properties may enable the creation of coatings with gradient release profiles, where different regions of the coating release active compounds at different rates based on their photopolymerization history. Marine coatings may benefit from these controlled release mechanisms to provide antifouling properties while minimizing environmental impact through targeted release of active compounds.

[0149] Consumer applications can leverage the wavelength-selective dissolution properties for various personal care and cosmetic products. Nail polish formulations may incorporate these materials to create color-changing or pattern-revealing effects, where exposure to specific wavelengths of light causes certain regions to dissolve and reveal underlying colors or patterns. The controlled dissolution behavior may enable the creation of nail polish systems with extended wear properties, where the outer layer provides initial color and protection while underlying layers are revealed through selective dissolution over time. Fragrance release applications may utilize the controlled dissolution properties to create perfumes or scented products with time-delayed or triggered release profiles. The encapsulation of fragrance compounds within photopolymerized matrices may enablecontrolled release when exposed to specific environmental conditions such as moisture, temperature changes, or light exposure. Personal care products may incorporate these materials to provide sustained release of active ingredients such as moisturizers, sunscreens, or therapeutic compounds.

[0150] Artistic and decorative applications may exploit the wavelength-selective properties to create dynamic visual effects and interactive artworks. Etchings and engravings may utilize these materials to create images or patterns that change over time through selective dissolution of different regions. Artists may create works that reveal hidden images or messages when exposed to specific wavelengths of light or when placed in contact with particular solvents. The controlled dissolution behavior may enable the creation of temporary artworks that evolve and change their appearance over predetermined time periods.Decorative coatings for architectural applications may incorporate these materials to create surfaces that change their texture or appearance in response to environmental conditions such as humidity, temperature, or light exposure. Interactive installations may utilize the wavelength-selective properties to create responsive surfaces that react to user interaction through light exposure or contact with specific solutions.

[0151] Photolithography applications may benefit from the precise spatial control of dissolution properties achievable through wavelength-selective exposure. Microelectronics manufacturing may utilize these materials as photoresists that can be selectively removed through dissolution processes after pattern exposure. The ability to create regions with different dissolution rates may enable the fabrication of complex three-dimensional microstructures through sequential exposure and dissolution steps. Optical device manufacturing may incorporate these materials to create waveguides, lenses, or other optical components with spatially varying properties. The controlled dissolution behavior may enable the creation of sacrificial layers or temporary supports that can be removed without affecting the final device structure. Microfluidics applications may utilize the selective dissolution properties to create channels, chambers, or other fluidic features through the removal of sacrificial material after the device fabrication is complete.

[0152] Sensor applications may leverage the wavelength-selective dissolution properties to create responsive detection systems. Chemical sensors may incorporate these materials as sensing elements that undergo dissolution when exposed to specific analytes, creating detectable changes in optical, electrical, or mechanical properties. Environmental monitoring sensors may utilize controlled dissolution mechanisms to provide time-integratedmeasurements of pollutant exposure or environmental conditions. The dissolution rate may correlate with the concentration or duration of exposure to target compounds, enabling quantitative analysis of environmental conditions. Biological sensors may incorporate these materials to detect the presence of specific enzymes, proteins, or other biomolecules that trigger dissolution through biochemical interactions. The spatial control of dissolution properties may enable the creation of sensor arrays where different regions respond to different analytes or concentration ranges. Food safety sensors may utilize controlled dissolution mechanisms to detect spoilage indicators or contamination in food and beverage products.

[0153] Water treatment applications may utilize the controlled release properties of these materials to provide sustained delivery of treatment chemicals. Aquarium water treatment systems may incorporate these materials to provide time-delayed release of pH buffers, biological supplements, or water conditioning agents. The controlled dissolution behavior may enable the maintenance of optimal water chemistry over extended periods without frequent manual intervention. Wastewater treatment plants may utilize these materials to provide controlled release of coagulants, flocculants, or biological treatment agents. The spatial control of dissolution properties may enable the creation of treatment systems with multiple release zones that provide different chemicals at different stages of the treatment process. Swimming pool and spa treatment systems may benefit from controlled release mechanisms that provide sustained delivery of sanitizers, pH adjusters, or other water treatment chemicals. Industrial water treatment applications may utilize these materials to provide controlled release of scale inhibitors, corrosion inhibitors, or biocides in cooling towers, boilers, or other water systems.

[0154] Food and beverage production may incorporate these materials for controlled release of processing aids, flavoring agents, or preservation compounds. Packaging applications may utilize the wavelength-selective dissolution properties to create active packaging systems that release antimicrobial agents, antioxidants, or other preservation compounds in response to specific environmental conditions. The controlled release mechanisms may extend product shelflife while maintaining food safety and quality. Beverage production may incorporate these materials to provide time-delayed release of flavoring compounds, creating products with evolving taste profiles. Food processing applications may utilize controlled dissolution mechanisms to provide sequential release of enzymes, catalysts, or other processing aids during manufacturing operations. The spatialcontrol of dissolution properties may enable the creation of packaging materials with different release zones that provide different active compounds based on the specific requirements of different product regions.ro 1551 Biomedical applications beyond drug delivery may utilize the controlled dissolution properties for various therapeutic and diagnostic purposes. Contrast agents for magnetic resonance imaging (MRI) or computed tomography (CT) scans may incorporate these materials to provide controlled release of contrast compounds with specific timing profiles. The dissolution behavior may be tailored to provide optimal contrast enhancement during specific phases of the imaging procedure. Microneedle arrays may utilize the wavelength-selective properties to create dissolvable microneedles that deliver therapeutic compounds through transdermal routes. The controlled dissolution of microneedle structures may enable sustained delivery of vaccines, hormones, or other therapeutic agents through the skin. Cell scaffolding applications may benefit from the controlled dissolution properties to create temporary support structures that dissolve as natural tissue regeneration occurs. Vasculature applications may utilize these materials to create temporary stents or other medical devices that dissolve after serving their therapeutic purpose.

[0156] Agricultural applications may leverage the controlled release properties for sustainable delivery of fertilizers, pesticides, and other agricultural chemicals. Fertilizer release systems may utilize the wavelength-selective dissolution properties to provide nutrients to plants over extended growing seasons. The controlled release mechanisms may reduce the frequency of fertilizer applications while maintaining optimal nutrient availability for plant growth. Pesticide release applications may benefit from controlled dissolution behavior that provides sustained pest control while minimizing environmental impact through targeted delivery. The spatial control of dissolution properties may enable the creation of agricultural films or coatings that provide different release rates in different zones based on crop requirements. Seed coating applications may incorporate these materials to provide controlled release of growth promoters, fungicides, or other seed treatment compounds. Irrigation system applications may utilize controlled dissolution mechanisms to provide water treatment chemicals or nutrients through irrigation water over extended periods.

[0157] Disinfection applications may utilize the controlled release properties to provide sustained antimicrobial activity in various environments. Surface disinfection systems may incorporate these materials to provide time-delayed release of antimicrobial agents on high-touch surfaces in healthcare facilities, public transportation, or other high-risk environments.The controlled dissolution behavior may enable sustained disinfection activity while minimizing the frequency of reapplication. Air purification systems may utilize controlled release mechanisms to provide antimicrobial compounds or odor control agents in ventilation systems. The wavelength-selective properties may enable the creation of disinfection systems that can be activated or deactivated through light exposure. Water disinfection applications may benefit from controlled release of chlorine, ozone, or other disinfectants in water distribution systems. The spatial control of dissolution properties may enable the creation of disinfection systems with multiple release zones that provide different antimicrobial agents based on the specific contamination risks in different areas.

[0158] SYSTEM HARDWARE

[0159] Multi-wavelength vat photopolymerization systems may utilize sophisticated optical hardware configurations to achieve precise wavelength control and spatial light patterning for the selective activation of different polymerization mechanisms within resin formulations. The optical systems may incorporate dichroic mirrors that selectively reflect or transmit specific wavelengths of light while allowing other wavelengths to pass through with minimal attenuation. Dichroic minors may be positioned at precise angles within the optical beam path to combine multiple wavelength sources into a single collimated beam that can be directed toward the digital micromirror device for spatial patterning. The dichroic mirror coatings may be designed with specific transmission and reflection characteristics that enable efficient separation and combination of UV and visible wavelengths with minimal crosstalk between the different optical channels. The angular positioning and alignment of dichroic mirrors may be adjustable to optimize the beam combining efficiency and ensure proper spatial registration between different wavelength channels. The optical system may incorporate multiple dichroic mirrors in series to enable the combination of three or more distinct wavelengths for applications requiring more complex polymerization control schemes.

[0160] Digital micromirror devices may serve as spatial light modulators that provide pixel-level control over the exposure patterns for each wavelength channel in the multiwavelength printing system. The digital micromirror device may contain an array of microscopic mirrors that can be individually tilted to either direct light toward the resin surface or deflect light away from the exposure area. The mirror switching speed may enable rapid sequential exposure of different wavelength patterns within a single layer exposurecycle, allowing for precise temporal and spatial control over the polymerization processes. The digital micromirror device may be synchronized with the wavelength switching mechanisms to ensure proper registration between the different exposure patterns. The resolution of the digital micromirror device may determine the minimum feature size achievable in the printed structures, with higher resolution devices enabling finer spatial control over the dissolution properties. The contrast ratio of the digital micromirror device may influence the sharpness of the boundaries between regions exposed to different wavelengths, affecting the precision of the selective solubility characteristics. Multiple digital micromirror devices may be employed in parallel configurations to enable simultaneous exposure of different wavelength patterns, reducing the total exposure time required for each layer.

[0161] Light-emitting diode arrangements may provide the primary illumination sources for the multi-wavelength photopolymerization systems, offering advantages in terms of wavelength stability, power efficiency, and thermal management compared to traditional lamp-based systems. The LED arrays may be configured with specific wavelength outputs that match the absorption characteristics of the photoinitiators and photosensitizers incorporated in the resin formulations. UV LEDs operating at wavelengths around 365 nm may provide the energy needed to activate photoacid generators for cationic polymerization, while visible LEDs operating at wavelengths around 405 nm may activate free radical photoinitiators for acrylate polymerization. The LED drive electronics may enable precise control over the light intensity and exposure duration for each wavelength channel, allowing for fine-tuning of the polymerization kinetics and crosslink density in different regions. Thermal management systems may be integrated with the LED arrays to maintain stable operating temperatures and prevent wavelength drift that could affect the polymerization selectivity. The LED arrays may be arranged in configurations that provide uniform illumination across the entire exposure area, with optical diffusers and homogenizing elements used to eliminate intensity variations that could lead to non-uniform polymerization.

[0162] Beam path configurations may be designed to minimize optical losses and ensure proper spatial registration between different wavelength channels throughout the optical system. The beam paths may incorporate collimating lenses that convert the divergent output from LED sources into parallel light beams suitable for projection through the digital micromirror device. Focusing optics may be positioned after the digital micromirror device to project the patterned light onto the resin surface with the appropriate magnification andnumerical aperture. The optical system may include beam expansion elements that increase the beam diameter to match the active area of the digital micromirror device, ensuring full utilization of the spatial light modulator capabilities. Polarization control elements may be incorporated to optimize the interaction between the light and the digital micromirror device, maximizing the contrast ratio and minimizing scattered light that could cause unwanted polymerization. The beam path may include monitoring photodiodes that measure the light intensity at various points in the optical system, enabling real-time feedback control of the exposure parameters. Optical filters may be positioned at strategic locations in the beam path to remove unwanted wavelengths or reduce background illumination that could interfere with the selective polymerization processes.

[0163] Alternative activation mechanisms may extend beyond traditional light-based systems to include various forms of directed energy that can selectively initiate polymerization reactions in specific regions of the resin material. Infrared light sources may provide localized heating that activates thermal initiators or accelerates polymerization kinetics in targeted areas without affecting the bulk material temperature. The infrared heating approach may enable the creation of temperature gradients within the resin that correspond to different degrees of polymerization and crosslinking, resulting in spatially controlled dissolution properties. X-ray and gamma ray sources may provide high-energy radiation that can directly initiate polymerization reactions or activate specialized radiationsensitive initiators incorporated in the resin formulations. The penetrating nature of high-energy radiation may enable polymerization initiation throughout the bulk of thick resin layers without the attenuation effects that limit the depth of penetration for UV and visible light. Electron beam systems may provide precise spatial control over polymerization initiation through focused electron beams that can be scanned across the resin surface in predetermined patterns. The electron beam approach may offer advantages in terms of spatial resolution and depth of penetration compared to photon-based activation methods.

[0164] Ink-jetting systems may enable the localized delivery of polymerization initiators to specific regions of the resin material, creating spatial patterns of reactivity that correspond to different dissolution characteristics after polymerization. The ink-jet approach may utilize piezoelectric or thermal print heads that deposit precise volumes of initiator solutions onto the resin surface or into the bulk material. Multiple ink-jet heads may be employed to deliver different types of initiators, enabling the creation of complex patterns with multiple polymerization mechanisms active in different regions. The ink-jet delivery system may beintegrated with the layer-by-layer printing process, allowing for the deposition of initiators during the build sequence to create three-dimensional patterns of reactivity. The initiator solutions may be formulated with appropriate viscosity and surface tension characteristics to ensure proper droplet formation and placement accuracy. Thermal initiators may be incorporated into the ink-jet formulations to provide temperature-activated polymerization that can be triggered through subsequent heating steps. The ink-jet approach may enable the use of initiators that are incompatible with bulk mixing in the resin formulation, expanding the range of polymerization chemistries that can be employed for selective dissolution control.

[0165] Encapsulated initiating species may provide temporal and thermal control over polymerization initiation through the use of nano-capsules or micro-capsules that release active compounds upon reaching specific temperature thresholds. The encapsulation approach may utilize polymer shells, lipid bilayers, or inorganic coatings that remain stable at ambient temperatures but rupture or become permeable when heated above a predetermined temperature. The capsule size distribution may be controlled to provide uniform release characteristics and prevent settling or aggregation during resin storage and handling.Multiple capsule populations with different release temperatures may be incorporated to create sequential polymerization events that occur at different stages of the thermal processing cycle. The encapsulated initiators may include photoacid generators, photobase generators, free radical initiators, or other reactive species that become active only after release from the protective capsules. The capsule loading may be optimized to provide sufficient initiator concentration for effective polymerization while maintaining the stability and shelflife of the resin formulation. The release kinetics of the encapsulated initiators may be tailored through the selection of capsule materials and wall thickness to provide controlled release profiles that match the desired polymerization timing.

[0166] Temperature-responsive capsule systems may enable precise spatial control over polymerization initiation through localized heating mechanisms that selectively trigger capsule rupture in specific regions of the resin material. Infrared heating, resistive heating elements, or induction heating may be employed to create localized temperature increases that exceed the capsule release threshold in targeted areas. The thermal activation approach may be combined with traditional light-based polymerization to create hybrid systems where both thermal and photochemical initiation contribute to the final material properties. The capsule release temperature may be selected based on the thermal stability of other resincomponents and the processing temperature requirements of the manufacturing system. Phase change materials may be incorporated into the capsule formulations to provide additional thermal buffering and ensure consistent release behavior across different environmental conditions. The encapsulated initiator approach may enable the creation of self-healing materials where dormant initiators are released in response to mechanical damage or environmental stress, triggering localized polymerization reactions that restore material integrity. The capsule design may incorporate targeting hgands or responsive elements that enable selective release in response to specific chemical or biological stimuli beyond temperature activation.

[0167] FIG. 7 is a schematic diagram that shows an example of a computing system 1600 that can be used to implement the techniques described herein. The computing system 1600 includes one or more computing devices (e.g. computing device 1610), which can be in wired and / or wireless communication with various peripheral device(s) 1680, data source(s) 1690, and / or other computing devices (e.g., over network(s) 1670). The computing device 1610 can represent various forms of stationary' computers (e.g., workstations, kiosks, servers, mainframes, edge computing devices, quantum computers, etc.) and mobile computers 1614 (e.g.. laptops, tablets, mobile phones, personal digital assistants, wearable devices, etc.). In some implementations, the computing device 1610 can be included in (and / or in communication with) various other sorts of devices, such as data collection devices (e.g., devices that are configured to collect data from a physical environment, such as microphones, cameras, scanners, sensors, etc.), robotic devices (e.g., devices that are configured to physically interact with objects in a physical environment, such as manufacturing devices, maintenance devices, object handling devices, etc.), vehicles (e g., devices that are configured to move throughout a physical environment, such as automated guided vehicles, manually operated vehicles, etc.), or other such devices. Each of the devices (e.g, stationary computers, mobile computers, and / or other devices) can include components of the computing device 1610, and an entire system can be made up of multiple devices communicating with each other. For example, the computing device 1610 can be part of a computing system that includes a network of computing devices, such as a cloud-based computing system, a computing system in an internal network, or a computing system in another sort of shared network. Processors of the computing device 1610 and other computing devices of a computing system can be optimized for different ty pes of operations, secure computing tasks, etc. The components shown herein, and their functions, are meant tobe examples, and are not meant to limit implementations of the technology described and / or claimed in this document.

[0168] The computing device 1610 includes processor(s) 1620, memory device(s) 1630, storage device(s) 1640, and interface(s) 1650. Each of the processor(s) 1620, the memory device(s) 1630, the storage device(s) 1640, and the interface(s) 1 50 are interconnected using a system bus 1660. The processor(s) 1620 are capable of processing instructions for execution within the computing device 1610, and can include one or more single-threaded and / or multi-threaded processors. The processor(s) 1620 are capable of processing instructions stored in the memory device(s) 1630 and / or on the storage device(s) 1640. The memory device(s) 1630 can store data within the computing device 1610, and can include one or more computer-readable media, volatile memory units, and / or non-volatile memory¬ units. The storage device(s) 1640 can provide mass storage for the computing device 1610, can include various computer-readable media (e.g, a floppy disk device, a hard disk device, a tape device, an optical disk device, a flash memory or other similar solid state memory7device, or an array of devices, including devices in a storage area network or other configurations), and can provide date security / encryption capabilities.

[0169] The interface(s) 1650 can include various communications interfaces (e.g., USB, Near-Field Communication (NFC), Bluetooth, WiFi, Ethernet, wireless Ethernet, etc.) that can be coupled to the network(s) 1670, peripheral device(s) 1680, and / or data source(s) 1690 (e.g., through a communications port, a network adapter, etc ). Communication can be provided under various modes or protocols for wired and / or wireless communication. Such communication can occur, for example, through a transceiver using a radio-frequency. As another example, communication can occur using light (e.g, laser, infrared, etc.) to transmit data. As another example, short-range communication can occur, such as using Bluetooth, WiFi, or other such transceiver. In addition, a GPS (Global Positioning System) receiver module can provide location-related wireless data, which can be used as appropriate by¬ device applications. The interface(s) 1650 can include a control interface that receives commands from an input device (e.g., operated by a user) and converts the commands for submission to the processors 1620. The interface(s) 1650 can include a display interface that includes circuitry- for driving a display to present visual information to a user. The interface(s) 1650 can include an audio codec which can receive sound signals (e.g., spoken information from a user) and convert it to usable digital data. The audio codec can likewise generate audible sound, such as through an audio speaker. Such sound can include real-timevoice communications, recorded sound (e.g., voice messages, music files, etc.), and / or sound generated by device applications.

[0170] The network(s) 1670 can include one or more wired and / or wireless communications networks, including various public and / or private networks. Examples of communication networks include a LAN (local area network), a WAN (wide area network), and / or the Internet. The communication networks can include a group of nodes (e.g., computing devices) that are configured to exchange data (e.g, analog messages, digital messages, etc.), through telecommunications links. The telecommunications links can use various techniques (e.g, circuit switching, message switching, packet switching, etc.) to send the data and other signals from an originating node to a destination node. In some implementations, the computing device 1610 can communicate with the peripheral device(s) 1680, the data source(s) 1690, and / or other computing devices over the network(s) 1670. In some implementations, the computing device 1610 can directly communicate with the peripheral device(s) 1680, the data source(s), and / or other computing devices.

[0171] The peripheral device(s) 1680 can provide input / output operations for the computing device 1610. Input devices (e.g., keyboards, pointing devices, touchscreens, microphones, cameras, scanners, sensors, etc.) can provide input to the computing device 1610 (e.g, user input and / or other input from a physical environment). Output devices (e.g. display units such as display screens or projection devices for displaying graphical user interfaces (GUIs)), audio speakers for generating sound, tactile feedback devices, printers, motors, hardware control devices, etc.) can provide output from the computing device 1610 (e.g, user-directed output and / or other output that results in actions being performed in a physical environment). Other kinds of devices can be used to provide for interactions between users and devices. For example, input from a user can be received in any form, including visual, auditory, or tactile input, and feedback provided to the user can be any form of sensory7feedback (e.g, visual feedback, auditory feedback, or tactile feedback).

[0172] The data source(s) 1690 can provide data for use by the computing device 1610, and / or can maintain data that has been generated by the computing device 1610 and / or other devices (e.g. data collected from sensor devices, data aggregated from various different data repositories, etc ). In some implementations, one or more data sources can be hosted by the computing device 1610 (e.g, using the storage device(s) 1640). In some implementations, one or more data sources can be hosted by a different computing device. Data can be provided by the data source(s) 1690 in response to a request for data from the computingdevice 1610 and / or can be provided without such a request. For example, a pull technology can be used in which the provision of data is driven by device requests, and / or a push technology can be used in which the provision of data occurs as the data becomes available (e.g., real-time data streaming and / or notifications). Various sorts of data sources can be used to implement the techniques described herein, alone or in combination.

[0173] In some implementations, a data source can include one or more data store(s) 1690a. The database(s) can be provided by a single computing device or network (e.g., on a file system of a server device) or provided by multiple distributed computing devices or networks e.g., hosted by a computer cluster, hosted in cloud storage, etc.). In some implementations, a database management system (DBMS) can be included to provide access to data contained in the database(s) (e.g., through the use of a query language and / or application programming interfaces (APIs)). The database(s), for example, can include relational databases, object databases, structured document databases, unstructured document databases, graph databases, and other appropriate types of databases.

[0174] In some implementations, a data source can include one or more blockchains 1690b. A blockchain can be a distributed ledger that includes blocks of records that are securely linked by cryptographic hashes. Each block of records includes a cryptographic hash of the previous block, and transaction data for transactions that occurred during a time period. The blockchain can be hosted by a peer-to-peer computer network that includes a group of nodes (e.g., computing devices) that collectively implement a consensus algorithm protocol to validate new transaction blocks and to add the validated transaction blocks to the blockchain. By storing data across the peer-to-peer computer network, for example, the blockchain can maintain data quality (e.g.. through data replication) and can improve data trust (e.g.. by reducing or eliminating central data control).

[0175] In some implementations, a data source can include one or more machine learning systems 1690c. The machine learning system(s) 1690c, for example, can be used to analyze data from various sources (e.g., data provided by the computing device 1610, data from the data store(s) 1690a, data from the blockchain(s) 1690b, and / or data from other data sources), to identify patterns in the data, and to draw inferences from the data patterns. In general, training data 1692 can be provided to one or more machine learning algorithms 1694, and the machine learning algorithm(s) can generate a machine learning model 1696. Execution of the machine learning algorithm(s) can be performed by the computing device 1610, or another appropriate device. Various machine learning approaches can be used to generatemachine learning models, such as supervised learning (e.g, in which a model is generated from training data that includes both the inputs and the desired outputs), unsupervised learning (e.g., in which a model is generated from training data that includes only the inputs), reinforcement learning (e.g., in which the machine learning algorithm(s) interact with a dynamic environment and are provided with feedback during a training process), or another appropriate approach. A variety of different types of machine learning techniques can be employed, including but not limited to convolutional neural networks (CNNs). deep neural networks (DNNs), recurrent neural networks (RNNs), and other types of multi-layer neural networks.

[0176] Various implementations of the systems and techniques described herein can be realized in digital electronic circuitry', integrated circuitry, specially designed ASICs (application specific integrated circuits), computer hardware, firmware, software, and / or combinations thereof. A computer program product can be tangibly embodied in an information carrier (e.g., in a machine-readable storage device), for execution by a programmable processor. Various computer operations (e.g., methods described in this document) can be performed by a programmable processor executing a program of instructions to perform functions of the described implementations by operating on input data and generating output. The described features can be implemented in one or more computer programs that are executable on a programmable system including at least one programmable processor coupled to receive data and instructions from, and to transmit data and instructions to, a data storage system, at least one input device, and at least one output device. A computer program is a set of instructions that can be used, directly or indirectly, by a computer to perform a certain activity or bring about a certain result. A computer program can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program product can be a computer- or machine-readable medium, such as a storage device or memory' device. As used herein, the terms machine-readable medium and computer-readable medium refer to any computer program product, apparatus and / or device (e.g., magnetic discs, optical disks, memory, etc.) used to provide machine instructions and / or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term machine-readable signal refers to any signal used to provide machine instructions and / or data to a programmable processor.

[0177] Suitable processors for the execution of a program of instructions include, by way of example, both general and special purpose microprocessors, and can be a single processor or one of multiple processors of any kind of computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer can also include, or can be operatively coupled to communicate with, one or more mass storage devices for storing data fdes. Such devices can include magnetic disks (e.g, internal hard disks and / or removable disks), magneto-optical disks, and optical disks. Storage devices suitable for tangibly embodying computer program instructions and data can include all forms of non-volatile memory, including by way of example semiconductor memory devices, flash memory devices, magnetic disks (e.g, internal hard disks and removable disks), magneto-optical disks, and optical disks. The processor and the memon can be supplemented by, or incorporated in, ASICs (application-specific integrated circuits).

[0178] The systems and techniques described herein can be implemented in a computing system that includes a back end component (e.g, a data server), or that includes a middleware component (e.g.. an application server), or that includes a front end component (e.g.. a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middlew are, or front end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g, a communication network). The computer system can include clients and servers, which can be generally remote from each other and typically interact through a network, such as the described one. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

[0179] Some non-limiting claims that are supported by the contents of the present disclosure are provided below.1. A resin material, comprising:one or more monofunctional monomers that are configured to photocure into a dissolvable material using a first polymerization mechanism;one or more multifunctional monomers having one or more chemical groups that are capable of reacting via a mechanism different than the first polymerization mechanism of the one or more monofunctional monomers; andone or more photoinitiators, co-initiators, or photosensitizers;wherein the resin material comprises a first plurality of material regions having a first dissolution rate that dissolve in a plurality of solvents after the resin material is exposed to light at a first range of intensities, durations of exposure, or dosages; andwherein the resin material comprises a second plurality of material regions with a second dissolution rate in the plurality of solvents that would dissolve the first plurality of material regions after the resin material is exposed to light at a second range of intensities, durations of exposure, or dosages, the second dissolution rate being different than the first dissolution rate.2. The resin material of example 1. wherein the second dissolution rate is lower than the first dissolution rate such that the first plurality of material regions are configured to be dissolved on a timescale where the second plurality of material regions undergo negligible dissolution.3. The resin material of example 2, wherein the second plurality' of material regions have a dissolution rate that is effectively zero.4. The resin material of any of examples 1 to 3, wherein the light in the first range of intensities or durations of exposure is at the same wavelength as light in the second range of intensities or durations of exposure.5. The resin material of any of examples 1 to 4, wherein the resin material is at least one of iteratively or simultaneously exposed to different dosages of patterned light to spatially segregate at least one of a soluble region or an insoluble region within the plurality of material regions.6. The resin material of example 5, wherein the resin material is configured to be used in a 3D printing process to create 3D structures with separate regions that are soluble and insoluble.7. The resin material of example 6, wherein the additive comprises about 1% to about 50% of the resin material composition and acts as a primary material imparting differential solubility'.8. The resin material of any of examples 1 to 7, wherein the first polymerization mechanism comprises free radical polymerization and the mechanism different than that of the one or more monofunctional monomers comprises cationic ring-opening polymerization. 9. The resin material of example 8, further comprising a free radical inhibitor selected from the group comprising hydroquinones, stable radicals, radical quenchers, and chain transfer agents.10. The resin material of example 9, wherein the one or more monofunctional monomers comprise isobomyl acrylate and the one or more multifunctional monomers comprise epoxide crosslinkers.11. The resin material of any of examples 1 to 10, wherein the photosensitizer is selected from the group consisting of methoxythi oxanthone, isopropylthioxanthone, 2-ethyl-9.10-dimethoxy anthracene, anthracene, chlorophyll, camphorquinone, and 5,7-diiodo-3-butoxy-6-fluorone.12. The resin material of any of examples 1 to 11, further comprising one or more bridging monomers that have one or more of the chemical groups of the one or more multifunctional monomers and one or more additional chemical groups capable of photocuring with the one or more monofunctional monomers.13. The resin material of any of examples 1 to 12, further comprising a base quencher added in a molar amount less than a molar amount of a photoacid generator to control extent of cationic polymerization.14. The resin material of example 13, wherein the base quencher is selected from the group consisting of tertiary amines, pyridine, alcohols, quaternary ammonium salts, organic bases, and ammonium hydroxide.15. The resin material of any of examples 1 to 14, wherein spatial control of light dosage enables control over local degree of solubility ranging from a maximum rate of solubility' along a range of dissolution rates that extend down to zero.16. A method of forming a three-dimensional object, comprising:irradiating a resin material with radiation of a specific wavelength at different intensities or durations of exposure to form a plurality of material regions with different chemical connectivities, with a first of the plurality of material regions being capable of dissolving in a plurality of solvents, and a second of the plurality of material regions exhibitingdissolution rates in said plurality of solvents that differs from the dissolution rates of the first plurality of material regions in the plurality of solvents.17. The method of example 16, wherein irradiating the resin material with radiation occurs in a vat photopolymerization three-dimensional printing process to create three-dimensional structures having soluble and insoluble regions.18. The method of example 17, wherein the vat photopolymerization comprises digital light processing using a digital micromirror device for spatial light patterning.19. The method of any of examples 16 to 18, further comprising dissolving one or more of the plurality of material regions w ith a fluid comprising one or more monomer components of the resin material.20. The method of example 19, further comprising recycling the plurality' of material regions by incorporating the fluid with dissolved material regions into anew' resin formulation.21. The method of any of examples 16 to 20, further comprising applying a heat treatment to alter the dissolution rates of one or more of the plurality of material regions.22. The method of example 21, wherein the heat treatment is performed at a temperature ranging from about 50°C to about 180°C.23. The method of example 22, wherein the heat treatment is performed in a non-reactive, non-volatile liquid medium to achieve neutral or near-neutral buoyancy conditions.24. The method of any of examples 16 to 23, further comprising performing one or more of radical acrylate polymerization, ring opening of epoxides and oxetanes, radical thiol-ene polymerization, ring opening of oxazolines, ionic thiol-epoxide polymerization, ionic thiolisocyanate polymerization, ring opening metathesis polymerization, or hydrosilylation on one or more of the first of the plurality of material regions or the second of the plurality of material regions.25. A resin material, comprising:one or more monofunctional monomers and one or more photoinitiators or photosensitizers that are capable of photocuring into a dissolvable material;one or more monomers having one or more chemical groups capable of undergoing a polymerization mechanism different than that of the one or more monofunctional monomers;one or more photoinitiators or photosensitizers that are configured to photocure: (i) said additional chemical groups to form a thermoset material, or (ii) the one or more monofunctional monomers and the said additional chemical groups to form a thermoset material;wherein the resin material comprises a solid with a first plurality of material regions that are capable of dissolving in a plurality of solvents after the resin material is exposed to light at a first wavelength, and the resin material comprises a solid with a second plurality of material regions having a different dissolution rate in the plurality of solvents that would dissolve the first plurality of material regions of the solid after the resin material is exposed to light at a second wavelength.26. The resin matenal of example 25. wherein the second plurality of material regions of the solid have a dissolution rate that is lower than a dissolution rate of the first plurality' of material regions of the solid such that the first plurality’ of material regions are configured to be dissolved on a timescale where the second plurality of material regions undergoes negligible dissolution.27. The resin material of example 26, wherein the second plurality of material regions have a dissolution rate that is effectively zero.28. The resin material of any of examples 25 to 27, wherein the resin material is configured to be used to print three-dimensional objects wherein different spatial regions of the three-dimensional object are exposed to different wavelengths of light during a printing process such that the different regions of the three-dimensional object have different dissolution rates. 29. The resin material of any of examples 25 to 28, wherein the first plurality of material regions of the solid are soluble in one or more components of the resin material, and wherein the second plurality of material regions of the solid resist dissolution in the one or more components of the resin material.30. The resin material of example 29, wherein the solid is configured to be used as a component of a second resin material that achieves the same differential solubility as the resin material of example 1.31. The resin material of any of examples 25 to 30, further comprising a multifunctional monomer having a plurality of the one or more chemical groups of the one or more monomers.32. The resin material of example 31, wherein the multifunctional monomer has zero or one or more functional groups that allow the multifunctional monomer to react with the one or more monofunctional monomers.33. The resin material of any of examples 25 to 32, wherein the one or more monofunctional monomers and the one or more photoinitiators or photosensitizers cures via a free radical mechanism.34. The resin material of any of examples 25 to 33, further comprising one or more bridging monomers that have one or more of the chemical groups of the one or more monomer and one or more additional chemical groups capable of photocuring with the one or more monofunctional monomers.35. The resin material of example 34, wherein the one or more monofunctional monomers comprise an acrylate, a methacrylate, or an acrylamide.36. The resin material of any of examples 25 to 35. wherein the one or more monomers that have the one or more additional chemical groups cures via an ionic mechanism.37. The resin material of example 36, further comprising one or more of: i) a weak base added in a molar amount less than a molar amount of a photoacid generator for a cationic mechanism, or ii) a weak acid added in a molar amount less than a molar amount of a photobase generator for an anionic mechanism.38. The resin material of example 37, wherein the one or more additional chemical groups comprise an epoxide ring.39. The resin material of any of examples 25 to 38, wherein the first wavelength is about 405 nm and the second wavelength is about 365 nm.40. A method of forming a three-dimensional object, comprising:irradiating a resin material with radiation of a plurality of wavelengths in a plurality' of locations along the resin material to form a solid with a plurality of material regions with different chemical connectivities, with a first of the plurality' of material regions being capable of dissolving in a plurality of solvents, and a second of the plurality of material regions exhibiting dissolution rates in said plurality of solvents that differs from the dissolution rates of the first plurality of material regions in the plurality of solvents,wherein irradiating the plurality of locations is performed either iteratively or simultaneously.41. The method of example 40, wherein irradiating the resin material with radiation occurs in a vat photopolymerization three-dimensional printing process to create three-dimensional structures having soluble and insoluble regions.42. The method of example 41. wherein the vat photopolymerization comprises digital light processing using one or more of a digital micromirror device for spatial light patterning, an LCD, or a laser.43. The method of any of examples 40 to 42, further comprising dissolving one or more of the plurality of material regions with a fluid comprising one or more monomer components of the resin material.44. The method of example 43, further comprising recycling the plurality of material regions by incorporating the fluid with dissolved material regions into anew resin formulation.45. The method of any of examples 40 to 44, wherein a heat treatment is applied to alter the dissolution rates of one or more of the plurality of material regions.46. The method of example 45, wherein the heat treatment is performed at a temperature ranging from about 50°C to about 180°C.47. The method of example 46, wherein the heat treatment is performed in a non-reactive, non-volatile liquid medium to achieve neutral or near-neutral buoyancy conditions.48. The method of any of examples 40 to 47, wherein the resin material comprises one or more monofunctional monomers and one or more photoinitiators or photosensitizers that are capable of photocuring into a dissolvable material, and one or more monomers that have one or more chemical groups capable of photocuring with one or more of the monofunctional monomers, with the one or more monofunctional monomers having one or more additional chemical groups capable of undergoing a polymerization mechanism different than that of the one or more monofunctional monomers.49. The method of any of examples 40 to 48, wherein the plurality of wavelengths comprise a first wavelength of approximately 405 nm and a second wavelength of approximately 365 nm.

[0180] One skilled in the art will appreciate further features and advantages of the disclosure based on the above-described embodiments. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. By way of example, the wavelength-selective photopolymerizationmaterials can be adapted for use in microfluidics applications, optical device manufacturing, environmental sensing systems, and controlled release applications in agriculture and water treatment. A person skilled in the art, in view of the present disclosures, will be able to adapt some or all of the various systems, devices, and methods disclosed herein for coating applications with selective dissolution properties, consumer products with time-delayed release characteristics, artistic and decorative applications with dynamic visual effects, and biomedical applications including contrast agents, microneedle arrays, and tissue scaffolding systems. All publications and references cited herein are expressly incorporated herein by reference in their entirety.

Claims

1. We claim:

1. A resin material, comprising:one or more monofunctional monomers that are configured to photocure into a dissolvable material using a first polymerization mechanism;one or more multifunctional monomers having one or more chemical groups that are capable of reacting via a mechanism different than the first polymerization mechanism of the one or more monofunctional monomers: andone or more photoinitiators, co-initiators, or photosensitizers;wherein the resin material comprises a first plurality of material regions having a first dissolution rate that dissolve in a plurality of solvents after the resin material is exposed to light at a first range of intensities, durations of exposure, or dosages; andwherein the resin material comprises a second plurality of material regions with a second dissolution rate in the plurality of solvents that would dissolve the first plurality of material regions after the resin material is exposed to light at a second range of intensities, durations of exposure, or dosages, the second dissolution rate being different than the first dissolution rate.

2. The resin material of claim 1, wherein the second dissolution rate is lower than the first dissolution rate such that the first plurality of material regions are configured to be dissolved on a timescale where the second plurality of material regions undergo negligible dissolution.

3. The resin material of claim 2, wherein the second plurality of material regions have a dissolution rate that is effectively zero.

4. The resin material of claim 1, wherein the light in the first range of intensities or durations of exposure is at the same wavelength as light in the second range of intensities or durations of exposure.

5. The resin material of claim 1, wherein the resin material is at least one of iteratively or simultaneously exposed to different dosages of patterned light to spatially segregate at least one of a soluble region or an insoluble region within the plurality of material regions.

6. The resin material of claim 5, wherein the resin material is configured to be used in a 3D printing process to create 3D structures with separate regions that are soluble and insoluble.

7. The resin material of claim 6, wherein the additive comprises about 1% to about 50% of the resin material composition and acts as a primary material imparting differential solubility.

8. The resin material of claim 1, wherein the first polymerization mechanism comprises free radical polymerization and the mechanism different than that of the one or more monofunctional monomers comprises cationic ring-opening polymerization.

9. The resin material of claim 8, further comprising a free radical inhibitor selected from the group comprising hydroquinones, stable radicals, radical quenchers, and chain transfer agents.

10. The resin material of claim 9, wherein the one or more monofunctional monomers comprise isobomyl acrylate and the one or more multifunctional monomers comprise epoxide crosslinkers.

11. The resin material of claim 1, wherein the photosensitizer is selected from the group consisting of methoxythi oxanthone, isopropylthioxanthone, 2-ethyl-9,10-dimethoxy anthracene, anthracene, chlorophyll, camphorquinone, and 5,7-diiodo-3-butoxy-6-fluorone.

12. The resin material of claim 1, further comprising one or more bridging monomers that have one or more of the chemical groups of the one or more multifunctional monomers and one or more additional chemical groups capable of photocuring with the one or more monofunctional monomers.

13. The resin material of claim 1, further comprising a base quencher added in a molar amount less than a molar amount of a photoacid generator to control extent of cationic polymerization.

14. The resin material of claim 13. wherein the base quencher is selected from the group consisting of tertiary amines, pyridine, alcohols, quaternary ammonium salts, organic bases, and ammonium hydroxide.

15. The resin material of claim 1, wherein spatial control of light dosage enables control over local degree of solubility ranging from a maximum rate of solubility along a range of dissolution rates that extend down to zero.

16. A method of forming a three-dimensional object, comprising:irradiating a resin material with radiation of a specific wavelength at different intensities or durations of exposure to form a plurality of material regions with different chemical connectivities, with a first of the plurality of material regions being capable of dissolving in a plurality of solvents, and a second of the plurality of material regions exhibiting dissolution rates in said plurality of solvents that differs from the dissolution rates of the first plurality of material regions in the plurality of solvents.

17. The method of claim 16, wherein irradiating the resin material with radiation occurs in a vat photopolymerization three-dimensional printing process to create three-dimensional structures having soluble and insoluble regions.

18. The method of claim 17, w herein the vat photopolymerization comprises digital light processing using a digital micromirror device for spatial light patterning.

19. The method of claim 16, further comprising dissolving one or more of the plurality of material regions with a fluid comprising one or more monomer components of the resin material.

20. The method of claim 19, further comprising recycling the plurality of material regions by incorporating the fluid with dissolved material regions into a new resin formulation.

21. The method of claim 16, further comprising applying a heat treatment to alter the dissolution rates of one or more of the plurality of material regions.

22. The method of claim 21 , wherein the heat treatment is performed at a temperature ranging from about 50°C to about 180°C.

23. The method of claim 22, wherein the heat treatment is performed in a non-reactive, non-volatile liquid medium to achieve neutral or near-neutral buoyancy conditions.

24. The method of claim 16. further comprising performing one or more of radical acrylate polymerization, ring opening of epoxides and oxetanes, radical thiol-ene polymerization, ring opening of oxazolines, ionic thiol-epoxide polymerization, ionic thiolisocyanate polymerization, ring opening metathesis polymerization, or hydrosilylation on oneor more of the first of the plurality of material regions or the second of the plurality of material regions.

25. A resin material, comprising:one or more monofunctional monomers and one or more photoinitiators or photosensitizers that are capable of photocuring into a dissolvable material;one or more monomers having one or more chemical groups capable of undergoing a polymerization mechanism different than that of the one or more monofunctional monomers;one or more photoinitiators or photosensitizers that are configured to photocure: (i) said additional chemical groups to form a thermoset material, or (ii) the one ormore monofunctional monomers and the said additional chemical groups to form a thermoset material;wherein the resin material comprises a solid with a first plurality of material regions that are capable of dissolving in a plurality of solvents after the resin material is exposed to light at a first wavelength, and the resin material comprises a solid with a second plurality of material regions having a different dissolution rate in the plurality of solvents that would dissolve the first plurality of material regions of the solid after the resin material is exposed to light at a second w avelength.

26. The resin material of claim 25, wherein the second plurality' of material regions of the solid have a dissolution rate that is lower than a dissolution rate of the first plurality' of material regions of the solid such that the first plurality of material regions are configured to be dissolved on a timescale where the second plurality of material regions undergoes negligible dissolution.

27. The resin material of claim 26, wherein the second plurality of material regions have a dissolution rate that is effectively zero.

28. The resin material of claim 25, wherein the resin material is configured to be used to print three-dimensional objects wherein different spatial regions of the three-dimensional object are exposed to different wavelengths of light during a printing process such that the different regions of the three-dimensional object have different dissolution rates.

29. The resin material of claim 25. wherein the first plurality of material regions of the solid are soluble in one or more components of the resin material, and wherein the secondplurality of material regions of the solid resist dissolution in the one or more components of the resin material.

30. The resin material of claim 29. wherein the solid is configured to be used as a component of a second resin material that achieves the same differential solubility as the resin material of claim 1.

31. The resin material of claim 25, further comprising a multifunctional monomer having a plurality of the one or more chemical groups of the one or more monomers.

32. The resin material of claim 31 , wherein the multifunctional monomer has zero or one or more functional groups that allow the multifunctional monomer to react with the one or more monofunctional monomers.

33. The resin material of claim 25, wherein the one or more monofunctional monomers and the one or more photoinitiators or photosensitizers cures via a free radical mechanism.

34. The resin material of claim 25, further comprising one or more bridging monomers that have one or more of the chemical groups of the one or more monomer and one or more additional chemical groups capable of photocuring with the one or more monofunctional monomers.

35. The resin material of claim 34, wherein the one or more monofunctional monomers comprise an acrylate, a methacrylate, or an acrylamide.

36. The resin material of claim 21, wherein the one or more monomers that have the one or more additional chemical groups cures via an ionic mechanism.

37. The resin material of claim 36, further comprising one or more of: i) a weak base added in a molar amount less than a molar amount of a photoacid generator for a cationic mechanism, or ii) a weak acid added in a molar amount less than a molar amount of a photobase generator for an anionic mechanism.

38. The resin material of claim 37. wherein the one or more additional chemical groups comprise an epoxide ring.

39. The resin material of claim 25. wherein the first wavelength is about 405 nm and the second wavelength is about 365 nm.

40. A method of forming a three-dimensional object, comprising:irradiating a resin material with radiation of a plurality of wavelengths in a plurality of locations along the resin material to form a solid with a plurality of material regions with different chemical connectivities, with a first of the plurality of material regions being capable of dissolving in a plurality of solvents, and a second of the plurality of material regions exhibiting dissolution rates in said plurality of solvents that differs from the dissolution rates of the first plurality of material regions in the plurality of solvents, wherein irradiating the plurality of locations is performed either iteratively or simultaneously.

41. The method of claim 40, wherein irradiating the resin material with radiation occurs in a vat photopolymerization three-dimensional printing process to create three-dimensional structures having soluble and insoluble regions.

42. The method of claim 41, wherein the vat photopolymerization comprises digital light processing using one or more of a digital micromirror device for spatial light patterning, an LCD, or a laser.

43. The method of claim 40, further comprising dissolving one or more of the plurality of material regions with a fluid comprising one or more monomer components of the resin material.

44. The method of claim 43, further comprising recycling the plurality of material regions by incorporating the fluid with dissolved material regions into a new resin formulation.

45. The method of claim 40. wherein a heat treatment is applied to alter the dissolution rates of one or more of the plurality of material regions.

46. The method of claim 45, wherein the heat treatment is performed at a temperature ranging from about 50°C to about 180°C.

47. The method of claim 46, wherein the heat treatment is performed in a non-reactive, non-volatile liquid medium to achieve neutral or near-neutral buoyancy conditions.

48. The method of claim 40, wherein the resin material comprises one or more monofunctional monomers and one or more photoinitiators or photosensitizers that are capable of photocuring into a dissolvable material, and one or more monomers that have one or more chemical groups capable of photocuring with one or more of the monofunctionalmonomers, with the one or more monofunctional monomers having one or more additional chemical groups capable of undergoing a polymerization mechanism different than that of the one or more monofunctional monomers.

49. The method of claim 40, wherein the plurality of wavelengths comprise a first wavelength of approximately 405 nm and a second wavelength of approximately 365 nm.

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