Self-organization and precise arrangement of superparticles at all scales.

Abstract

A method for assembling building blocks into supraparticles is disclosed, comprising: applying a first solvent onto a template of patterned recessed regions to wet the surfaces of the recessed regions; applying a second solvent onto the template of patterned recessed regions, wherein the building blocks are suspended in the second solvent; wherein the first and second solvents are incompletely miscible such that the interfacial surface tension between the first and second solvents is negligible; and wherein droplets of the second solvent spread droplets of the first solvent within the recessed regions, thereby assembling the building blocks into supraparticles within the recessed regions.

Description

Technical Field

[0001] [Government Clause] This invention was made with government support under Grant No. DMR-1810485 from the National Science Foundation (NSF). The United States Government has certain rights in this invention.

[0002] [Technical Field] The present invention generally relates to methods of organizing building blocks into superparticles, and more particularly, to methods of organizing microscopic building blocks or nanoparticles into superparticles.

Background Art

[0003] The ability to self-organize individual building blocks into ordered superparticles is a phenomenon known in natural systems (e.g., proteins) for obtaining new functionality. Regulating the self-organization of superparticles in an accurate and controlled manner not only helps to realize their potential uses, but also advances the fundamental understanding of self-organization in nature. Despite recent developments, it remains poorly understood how to develop universal, scalable, and robust self-organization strategies for superparticles across scales ranging from nano-length to macro-length. Current approaches are mostly limited in size, require chemical modification of the building blocks and cumbersome manufacturing procedures, and vary significantly depending on the building blocks used.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Emulsification-based self-assembly methods are ideal for superstructuring due to their simplicity and the fact that they do not require chemical modification. However, their long-standing drawbacks include the polydisperse size distribution of emulsion droplets, the unpleasantness caused by the use of emulsifiers (e.g., surfactants), and the difficulty of precise placement due to their unfixed fluid properties. These factors, collectively, hinder the ability to define the size, uniformity, and applications of self-assembled superparticles. [Means for solving the problem]

[0005] [overview] According to one embodiment, a method for organizing building blocks into superparticles, wherein the method includes: A step of adding a first solvent to a template of a patterned concave region in order to wet the surface of the concave region; The step of adding a second solvent to the template of the patterned concave region, wherein the building block is suspended in the second solvent; Here, the first solvent and the second solvent are imperfectly miscible, and as a result, the surface tension at the interface between the first solvent and the second solvent is negligible; and, Here, the droplet of the second solvent diffuses the droplet of the first solvent within the concave region, thereby organizing the building blocks into superparticles within the concave region.

[0006] According to another embodiment, the solvent system includes: A first solvent, where the first solvent is 1-butanol; A second solvent, where the second solvent is water; A building block configured to be suspended in the second solvent and organized into superparticles, wherein the building block is selected from the group consisting of SiO2 nanoparticles, Fe3O4 nanoparticles, polydopamine (PDA) nanoparticles, gold nanoparticles, CdTe quantum dots, FeOOH nanorods, and Fe2O3 nanodiscs; and, Here, the solubility between the first solvent and the second solvent ranges from 0.5% by weight to 35% by weight. [Brief explanation of the drawing]

[0007] [Figure 1] Figures 1a-1e are schematic diagrams of the self-organization of superparticles in a concave region based on two types of imperfectly miscible solvents. [Figure 2] Figures 2a-2h show SEM images of superparticles constrained within template micropores (Figures 2a and 2b), SEM images of superparticles exposed by incomplete etching of the template surface using oxygen plasma treatment (Figure 2c), SEM images of superparticles in cross-section (Figure 2d), dark-field optical microscope images (Figure 2e), SEM images of superparticles recovered after template removal (Figures 2f and 2g), and the corresponding size distribution of the superparticles (Figure 2h). [Figure 3] Figures 3a-3h illustrate the steps for adjusting the size of organized superparticles by increasing the nanoparticle concentration in the solution. [Figure 4] Figures 4a-4e illustrate the steps for adjusting the size of the organized superparticles by increasing the size of the micropores in the template. [Figure 5] Figure 5 is a SEM image of superparticles constructed from various nanostructured materials having diverse shapes and compositions, used as building blocks. [Figure 6] Figure 6 shows the self-organization of superparticles in the range from millimeters (right) to nanometers (left). [Figure 7] Figures 7a and 7b illustrate the steps for adjusting the morphology of superparticles under an external magnetic field, where Figure 7a is an SEM image of the morphological evolution of organized Fe3O4 superparticles from a quasi-spherical structure to an elliptical structure by varying the strength of the applied magnetic field, and Figure 7b is an SEM image of one-dimensional (1D) and head-tail elliptical superparticles under magnetic organization. [Figure 8] Figures 8a–8d are schematic diagrams of the self-organization mechanism of tumbler-like superparticles under a magnetic field (Figure 8a), optical images (Figure 8b) and SEM images (Figure 8c) of tumbler-like superparticles of SiO2 and Fe3O4 nanoparticles as building blocks, and SEM images (Figure 8d) of one-dimensional (1D) and head-tail chain tumbler-like superparticles aligned along the magnetic field. [Figure 9] Figures 9a-9d illustrate the organization of superparticles within various template pores, where Figures 9a-9c are SEM images of SiO2 superparticles organized within cylindrical, cylindrical-dimer, and inverted pyramidal micropore-array films, respectively. This is also applicable to Figure 9d, cylindrical trimer and cylindrical tetramer micropore-array films, as well as micropore-arrays with irregular shapes. Here, the irregular shapes of the micropores in Figure 9d evolved from cylindrical tetramer micropores when their inner walls were broken. [Figure 10] Figures 10a-10f illustrate the steps involved in organizing chitosan superparticles of various sizes by reducing the concentration of chitosan monomer. [Figure 11] Figures 11a-11c illustrate superparticles organized from biological building blocks, such as casein protein (Figure 11a), fish sperm DNA (Figure 11b), and cells of Micrococcus lysodeikticus (Figure 11c). [Figure 12]Figures 12a - 12c relate to superparticles organized from ions, where the growth of cubic - like micro - crystals of sodium chloride (NaCl) (Figure 12a), the growth of "rice - grain - like" micro - crystals of sodium sulfite (Na2SO3) with a long crack in the center (Figure 12b), and the growth of "flower - like" micro - crystals of sodium sulfate (Na2SO4) (Figure 12c) are shown. [Figure 13] Figures 13a - 13e relate to the production of a micro - pore - array PS film replicated from a silicon wafer via a PDMS soft - lithography strategy.

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Mode for Carrying Out the Invention

[0019] [Detailed Description] This disclosure relates to a method for the self-organization and precise positioning of superparticles at any scale in a concave region, based on two or more solvents having imperfect miscibility (e.g., water in butanol or pentanol). By utilizing the imperfect miscibility of these solvents, transient emulsion droplets containing target building blocks can be generated in a patterned concave region on a substrate.

[0020] According to one embodiment, for example, when water diffuses into 1-butanol, the emulsion droplets decrease, driving the self-assembly of the building blocks within the template, and distinct superparticles having a positional order defined by the template are generated. Furthermore, the assembly process can be modulated by applying external stimuli (e.g., a magnetic or electric field). This method is relatively simple, time-saving, low-cost, scalable, and versatile. These are important advantages, for example, for the future development of advanced precision manufacturing. The superparticles may be used, for example, for the nanoscale fabrication of electronic displays, display panels, semiconductor devices, electronic devices, drug carriers and biosensors, protein chips, cell sorting, and / or energy generation and storage materials.

[0021] In another embodiment, the disclosure describes a method for generating and precisely positioning superparticles in a designed concave region based on two or more solvents having imperfect miscibility. In this application, two or more solvents having imperfect miscibility may be defined as solvents that may be imperfectly miscible with each other. The solubility between the solvents may be, for example, from 0.5% to 35% by weight, more preferably from 15% to 30% by weight, for example, but not limited to, water (20.1% by weight) in 1-butanol.

[0022] According to one embodiment, the solubility between the solvents may be important for the formation of transient emulsion droplets containing the target building block. For example, if the solubility is too high, the first solvent and the second solvent will mix relatively quickly without the formation of transient emulsion droplets. Alternatively, if the solubility is too low, the first solvent and the second solvent are likely to remain in separate phases, making it difficult for emulsion droplets to form.

[0023] Furthermore, with respect to the building blocks (e.g., nanoparticles), such as magnetic building blocks and non-magnetic building blocks, if the (second) solvent is depleted (by diffusion into the first solvent), aggregation of the building blocks progresses.

[0024] Furthermore, the building blocks are preferably dispersible only in the second solvent but not in the first solvent. Therefore, when the second solvent diffuses into the first solvent, the building blocks lose their colloidal stability and thus aggregate, since they are not dispersible in the first solvent.

[0025] Figures 1a-1e show schematic diagrams of the self-assembly and configuration procedures based on two imperfectly miscible solvents. The detailed steps of this method are described below.

[0026] Step 1:

[0027] As shown in Figure 1a, one of the pure solvents (hereinafter referred to as the "first solvent") is first introduced into the substrate to wet and fill a plurality of concave regions within the substrate. The first solvent may be introduced into the substrate by, for example, dropping, dipping, or wetting. The plurality of concave regions may be, for example, pores and grooves in the form of an array and / or an irregular pattern. The size of the concave regions is not limited to any particular size, but should be, for example, greater than or equal to the size of the building block (e.g., solid particles). The plurality of concave regions can be fabricated on the substrate by, for example, conventional lithography methods, imprinting methods, breath-figure methods, etc.

[0028] Step 2:

[0029] The building blocks are dispersed and suspended in a second solvent (hereinafter referred to as the "second solvent"). The building blocks include, but are not limited to, solid particles, polymers, molecules, ions, etc. The size of the building blocks may range, for example, from atoms to micrometers. According to one embodiment, one of the two solvents is considered a suspension solvent for solid particles, and preferably, a solvent that better disperses the building blocks is selected as the suspension solvent. For example, mechanical vibration or stirring and / or sonication can be used to improve the dispersion of the building blocks in the suspension solvent (i.e., the second solvent).

[0030] Step 3:

[0031] Next, as shown in Figure 1b, a second solvent in which the building blocks are suspended is introduced into the substrate. Because the first and second solvents are imperfectly miscible, the first solvent present in multiple recessed regions is replaced and filled with the suspended solvent, e.g., the second solvent, as shown in Figure 1c. The second solvent can be introduced onto the substrate by, for example, dropping, dipping, and wetting. According to one embodiment, the volume of the second solvent is at least twice the volume of the first solvent remaining on the substrate. The substitution process occurring in multiple recessed regions may be due to the diffusion of the first solvent into the second solvent phase, and the time consumed for this substitution process may vary from a few milliseconds (ms) to several days (d), depending on the mutual solubility of the first and second solvents.

[0032] Step 4:

[0033] A relatively large amount of the first solvent in a pure form (e.g., pure first solvent) can be used as a sweeping solvent, which is then introduced onto the substrate to remove any excess second solvent from the substrate surface. For example, as shown in Figure 1d, removing the excess second solvent from the substrate allows the first solvent to form droplets of the second solvent, isolated in each of a plurality of concave regions. According to one embodiment, the volume of the pure first solvent should be at least five times the volume of the second solvent used in step 3 to ensure that the excess second solvent is completely removed. A relatively large amount of the pure first solvent may be introduced by, for example, dropping, dipping, washing, etc.

[0034] Step 5:

[0035] By utilizing the imperfect miscibility of the first and second solvents, droplets of the second solvent formed in the concave region diffuse into the first solvent phase until the droplets of the second solvent disappear. In an additional embodiment, building blocks suspended in the droplets of the second solvent are encapsulated and therefore organized within the concave region during the diffusion process. The time it takes for the droplets of the second solvent to diffuse into the first solvent may range from, for example, several milliseconds (ms) to several hours (h). This depends on the mutual solubility of the first solvent and the aforementioned solvent. The amount of building blocks in each of the multiple concave regions may be adjustable, for example, by changing the concentration of building blocks suspended in the solvent and / or the size of the concave region used as a template. In the aforementioned concave region, the compacted building blocks may, but are not limited to, spherical structures (Figure 1e), elliptical structures densely packed with solid particles, colloidosomes, biological structures, crystals, or irregular arrangements of solid particles.

[0036] In another embodiment, an external stimulus (e.g., a magnetic field or electric field) may also be applied during the diffusion process to assist in the organization and arrangement of the superparticles within the concave region. The magnetic field may be used to deform the shape of the superparticles.

[0037] Example 1: Steps for organizing solid particles into superparticles in a honeycomb pore-array film based on a water / 1-butanol system.

[0038] According to the Young-Laplace law, the Laplace pressure inside an emulsion droplet can be determined by dividing the interfacial surface tension of the droplet by its radius. Since water and 1-butanol exhibit an imperfectly miscible system, the interfacial surface tension between water and 1-butanol can be considered negligible during the emulsification process. In a further embodiment, this negligible surface tension allows for relatively easy and precise adjustment of the size of the emulsion droplet within the concave region (e.g., pore) of the template by applying a minimal external force to the system (e.g., fluid-shear force induced by sweeping with 1-butanol). Because the Laplace pressure inside the emulsion droplet is negligible, the emulsion droplet is free from clumping and breaking without the need for an emulsifier. These characteristics are important for the self-assembly of ultraparticles across a wide range of dimensions demonstrated, which can also offer significant advantages compared to other immiscible emulsion-based self-assembly methods. For example, microfluidic self-assembly based on miniaturized channel tips for manipulating fluid emulsifications struggles with relatively complex procedures, relatively low yields, and time-consuming operations, and requires the application of high-pressure microflow and narrowing of microchannels to reduce the size of the emulsion droplets to a few micrometers. Furthermore, surfactants are required to help prevent these immiscible emulsion systems from cohesive. This can lead to the system potentially being toxic if it is intended for biological applications.

[0039] A water / 1-butanol system was used as an imperfectly miscible solvent. The solubility of water in 1-butanol and 1-butanol in water at 25°C was 20.1% by weight and 7.7% by weight, respectively. The honeycomb pore-array film, which has a hexagonal packed structure, can be obtained by the breath-figure method, where the size of the quasi-spherical pores is on the micrometer scale. For example, nanometer-scale spherical solid particles can be used, and these solid particles are preferably well dispersed in the aqueous phase. Figures 2a-2h show the results regarding the self-assembly of superparticles in a honeycomb pore-array film based on the water / 1-butanol system.

[0040] As shown in Figures 2a-2h, the superparticles formed within the pores of the honeycomb pore-array film exhibit a well-ordered spherical structure. Figures 3a-3h and 4a-4e show that the size of the organized superparticles can be adjusted by varying the concentration of solid particles in the aqueous phase and by varying the size of the pores in the honeycomb pore-array film, respectively. Figure 5 shows the self-assembly of superparticles using various types and shapes of building blocks, demonstrating broad versatility. Figure 6 illustrates the results for the self-assembly of superparticles having sizes ranging from nanometers to millimeters, showing that superparticles can be prepared at any scale by directly controlling the size of the template and the concentration of the building blocks using the method of this disclosure.

[0041] Example 2: Organization of superparticles under an external field

[0042] According to another embodiment, if the building block is capable of responding to external stimuli, the shape of the superparticles organized within the concave region can be tuned using such external stimuli, including, but not limited to, magnetic particles capable of responding to a magnetic field. For example, a water / 1-butanol system was selected as an imperfectly miscible solvent, and magnetic nanoparticles (e.g., Fe3O4) dispersed in the aqueous phase were used. According to one embodiment, the external magnetic field was applied perpendicularly through the substrate during the course of the entire process. As shown in Figure 7a, the magnetic Fe3O4 nanoparticles can be transformed from quasi-spherical superparticles to elliptical superparticles by organizing them in the external magnetic field while increasing the magnetic field strength. By organizing the magnetic nanoparticles into one-dimensional (1D) chains along the direction of the field within the z-emulsified droplets, the elliptical superparticles become elongated, resulting in a larger aspect ratio (L / D, length to diameter) at relatively stronger magnetic fields (Figure 7a). When released from the template and redispersed in 1-butanol, these elliptical superparticles remain structurally stable and, as shown in Figure 7b, further align along the magnetic field into a continuous 1D long chain and head-tail chain. Furthermore, by combining magnetic and non-magnetic nanoparticles, the superparticles may change, for example, from ellipsoidal to tumbler-like forms. Figures 8a-8d show tumbler-like superparticles organized from a mixture of Fe3O4 nanoparticles (115 ± 27 nm) and SiO2 nanoparticles (220 ± 16.7 nm) under a magnetic field according to one embodiment.

[0043] Example 3: Steps for organizing ultraparticles in various template pores

[0044] Apart from the honeycomb pore-array film described above, the disclosed method and system are also suitable for pore-array films of various forms, e.g., cylindrical (Figure 9a), cylindrical-dimer (Figure 9b), inverted-pyramidal (Figure 9c), and irregular pore forms (Figure 9d). According to one embodiment, similar superparticles, despite differences in morphology and periodicity, were well organized in all micropore-array films. For example, almost all of the superparticles were selectively deposited at the inner boundaries of the micropore walls to effectively reduce their surface energy. For example, the superparticles were deposited at the bottom tip of the inverted-pyramidal pores, where the potential energy is lowest (Figure 9c). Thus, these results demonstrate an effective strategy for selectively depositing the superparticles at a targeted location, which requires only pre-designing the pore-array.

[0045] Example 4. Steps for organizing superparticles from molecular and ionic building blocks.

[0046] In addition, solid particles and biomacromolecules (e.g., chitosan, casein proteins, fish sperm DNA, and Micrococcus living cells) can also be self-organized into unique superparticles using the same methods as described above (Figures 10a-11c).

[0047] Furthermore, this superstructuring strategy is not limited to the self-assembly of nanostructured molecules or polymer molecules, but can also be applied to the growth of crystals of ionic compounds in a constrained space provided by the template. Figures 12a-12c show the growth of "cuboid-like" microcrystals of NaCl, "rice grain-like" microcrystals of Na2SO3, and "flower-like" microcrystals of Na2SO4, representing cubic, monoclinic, and orthorhombic systems, respectively.

[0048] The ability to deposit ultraparticles at specific locations enables unique properties for certain technologies, such as the functionalization of biosensors, the nanoscale fabrication of protein chips, and cell sorting. In other ultraparticle self-assembly methods, such as those using complex techniques (e.g., AFM, lithography), a transfer process is generally required to position the ultraparticles in the targeted space, which is typically more difficult with nanoscale ultraparticles, and the ultraparticles are damaged due to the limited precision and yield of the positioning.

[0049] In further embodiments, the disclosed method, based on an imperfectly miscible solvent, provides a relatively low-cost and relatively high-throughput method for constructing homogeneous superparticles. Furthermore, the disclosed method ensures that the superparticles are precisely positioned within a given space without any structural damage. Due to the high degree of controllability over the size of the superparticles, the applicability to building blocks of a wide range of dimensions, compositions, and forms, and the ability to organize at any scale, this approach has the potential to have significant impact not only on materials science but also on other fields, such as data storage, bio- and chemical sensing, and biomedicine.

[0050] Nanoparticle synthesis

[0051] Synthesis of SiO2 nanoparticles:

[0052] SiO2 nanoparticles can be prepared by a modified Stober method. According to one embodiment, in the synthesis of SiO2 nanoparticles with a size of approximately 220 nm, 0.86 mL of tetraethyl orthosilicate (TEOS), 28 mL of ethanol, 4.3 mL of water, and 0.65 mL of ammonia (NH4OH, 28%) solution may be mixed. This mixture was reacted at room temperature for 4 hours with magnetic stirring. The SiO2 nanoparticles may be recovered by centrifugation, washed several times with water and ethanol, and finally redispersed in water for further use.

[0053] Synthesis of Fe3O4 nanoparticles:

[0054] Fe3O4 nanoparticles can be prepared by a hydrolysis process in a diethylene glycol (DEG) solution under high temperature and nitrogen protection. First, 50 mmol of NaOH powder was dissolved in 20 mL of DEG by heating at 120°C for 1 hour under a nitrogen atmosphere to obtain an NaOH / DEG stock solution. This mixture was stored at 70°C. (Approximately 115 nm) 3 To synthesize Fe3O4 nanoparticles, a mixture of poly(acrylic acid) (PAA, 4 mmol), iron chloride (FeCl3, 0.4 mmol), and DEG (17 mL) was heated to 220 °C for 30 minutes with vigorous stirring. Then, 1.85 mL of NaOH / DEG stock solution was rapidly added to the hot mixture. After further reaction at 220 °C for 1 hour, relatively large Fe3O4 nanoparticles were obtained, approximately 10 nm in size. 4To synthesize Fe3O4 nanoparticles, a mixture of PAA (4 mmol), FeCl3 (2 mmol), and DEG (10 mL) was heated at 220°C for 30 minutes. Then, 4.5 mL of NaOH / DEG stock solution was rapidly added to the hot mixture. Ten minutes after the reaction, FeCl3 (2 mmol) and NaOH / DEG stock solution (3 mL) were rapidly added to the hot mixture. After another 15 minutes of the reaction, relatively small Fe3O4 nanoparticles were obtained. Both final products were recovered by centrifugation, washed several times with ethanol and water, and then redispersed in water for further use.

[0055] Synthesis of polydopamine (PDA) nanoparticles:

[0056] To synthesize PDA nanoparticles of approximately 200 nm, 2 mL of NH4OH (28%), 40 mL of ethanol, and 90 mL of water may be mixed gently with stirring at room temperature for 30 minutes. Then, 0.5 g of dopamine hydrochloride dissolved in 10 mL of water is added to the mixture, and the mixture is reacted at room temperature in air for 48 hours. The PDA nanoparticles may be recovered by centrifugation, washed three times with water, and redispersed in water for further use.

[0057] Synthesis of gold nanoparticles:

[0058] A mixture of 0.035 mL of chloroauric acid (HAuCl4, 1 M), 1.4 mL of poly(diallyldimethylammonium) chloride (PDDA), 0.35 mL of hydrochloric acid (HCl), and 70 mL of ethylene glycol (EG) was sealed in a glass vial and reacted in an oil bath at 220°C for 30 minutes without stirring. After the reaction, the mixture containing the Au nanocrystalline colloid was allowed to cool naturally to room temperature, and then a further volume of (AuCl4) was added. -The corners and sharper edges of the Au nanocrystals were removed by adding HAuCl4 solution (where the molar ratio of ions to Au NPs is 1:40). The final gold nanoparticle product was recovered by centrifugation, rinsed three times with water, and may be redispersed in water for further use.

[0059] Synthesis of water-soluble CdTe quantum dots:

[0060] CdTe quantum dots may be prepared by mixing 16 mL of cadmium chloride (CdCl2, 0.04 M), 400 mg of trisodium citrate dihydrate, 400 mg of sodium borohydride (NaBH4), 4 mL of sodium tellurite (Na2TeO3, 0.01 M), 200 mg of mercaptosuccinic acid (MSA), and 184 mL of water in a flask with vigorous stirring. When the mixture turns green, a condenser is attached to the flask, and the mixture is refluxed under air conditions for 5 hours. The final product may be recovered by centrifugation, washed repeatedly with ethanol and water, and redispersed in water for further use.

[0061] Synthesis of FeOOH nanorods:

[0062] A mixture of 0.405 g of FeCl3·6H2O, 4.05 mg of NaHPO4, and 75 mL of water was transferred to a Teflon autoclave, sealed, and then held at 105°C for 48 hours. The final product may be recovered by centrifugation, rinsed with water, and redispersed in water for further use.

[0063] Synthesis of Fe2O3 nanodiscs:

[0064] As previously reported 10Fe2O3 nanodiscs can be prepared by an alcohol-thermal reaction. Briefly, a mixture of 1.09 g of FeCl3·6H2O, 5 g of sodium acetate, 2.8 mL of water, and 40 mL of ethanol was sealed in a Teflon autoclave and then held at 180 °C for 12 hours. The final product may be washed with water, recovered by centrifugation, and redispersed in water for further use.

[0065] Preparation of various hole array films as templates

[0066] Honeycomb microporous array polystyrene (PS) film:

[0067] This honeycomb microporous array film was prepared by the breath-figure method. First, solid PS (molecular weight ≈ 192,000) was dissolved in chloroform solvent to produce a 3.0 wt% PS precursor solution. Next, 350 μL of the PS solution was poured onto a glass coverslip (18 cm × 18 cm) in a sealed container. Then, the PS solution was blown over at room temperature for 10 minutes using a stream of water vapor-containing air (85% humidity) at a flow rate of 200 sccm. When the chloroform solvent was evaporated and the system was cooled, numerous water droplets may condense from the moist stream and then organize into a monolayer of ordered arrays on the surface of the PS solution. After the chloroform solvent and water droplets had completely evaporated, a honeycomb microporous array film was obtained. The micropore size in the film was adjusted by varying the volume of PS solution used and the condensation time.

[0068] Other microporous array PS films:

[0069] The fabrication process for other micro-perforated array PS films with various patterns was divided into two steps. The first step involved manufacturing micro-perforated array silicon (Si) wafers by further combining conventional photolithography strategies with an etching process. Briefly, for cylindrical micro-perforated array Si wafers, such as dimer-, trimer-, and tetramer-micro-perforated arrays, the Si wafer was patterned using the aforementioned photolithography technique and then etched by deep reactive-ion etching with SF6 gas. For inverted pyramidal array Si wafers, a Si wafer with a 300 nm thick silicon oxide (SiO2) layer was patterned through a photolithography process and then etched by a wet etching process. More specifically, the SiO2 layer was first etched with a buffered oxide etchant (BOE) for 6 minutes, and then the exposed silicon was etched with a potassium hydroxide solution (6 wt%) in a 90°C water bath for 1 hour. These Si wafers may be washed several times with acetone, ethanol, and water.

[0070] A second step was designed to replicate these Si wafers using a PDMS (polydimethylsiloxane) soft-lithography strategy, with the wafers serving as molds. First, to avoid adhesion of the PDMS molds to the Si wafers, these wafers may be treated with trimethylchlorosilane (TMCS) vapor for 15 minutes. Then, a mixture of PDMS elastomer and cross-linker in a 10:1 ratio was poured onto the Si wafers and cured at 70°C for 1 hour. Subsequently, the PDMS molds of the reverse-pattern arrays were replicated by peeling them off the Si wafers. Based on these PDMS molds, a PS / DMAC (N,N-dimethylacetamide) solution (5 wt%) was then poured onto the PDMS molds and dried at 60°C for 6 hours to completely evaporate the DMAC solvent. Finally, PS micro-porous array films with the corresponding patterns could be fabricated by peeling them off the PDMS molds.

[0071] Description of the manufacturing of microperforated array PS films replicated from silicon wafers using a PDMS soft lithography strategy.

[0072] 5-mm-sized hole array films, and 500-nm-sized hole array films:

[0073] A 5-mm-sized pore array film was prepared using a 3D printer. The printing precursor was acrylonitrile butadiene styrene (ABS). A 500 nm-sized pore array film was prepared by a modified in-situ polymerization process at the air-water interface. Briefly, first, a monolayer of 2D colloidal crystals (500 nm PS nanoparticles) was organized on the surface of an aqueous pyrrole monomer solution (0.8 wt%) in water) using an interfacial self-assembly method. The system was allowed to stand for 2 hours to allow the pyrrole monomer to expand into PS nanoparticles. Next, 200 μL of an aqueous FeCl3 solution (1 M) was added to the system to initiate polymerization coating of the pyrrole monomer on the water-immersed portion of the PS nanoparticle monolayer, and this was sustained at room temperature for 24 hours. A polypyrrole film having an upper-opening nanoporous array was prepared after removing PS nanoparticles with tetrahydrofuran (THF). The final product was rinsed several times with THF and water. Microporous array polypyrrole films with various periodic structures can be obtained by using PS nanoparticles of various sizes.

[0074] Template-based support emulsification strategies for self-organization

[0075] The microporous array film may first be wetted with 1-butanol. Then, an aqueous solution containing building blocks was dropwise poured onto the wetted porous array film (the solubility limit of water in 1-butanol is 20.4% w / w at 25°C). After 5 minutes, the aqueous solution was rapidly swept with a large amount of pure 1-butanol. Finally, a uniform superstructure can be generated within the micropores of the film. The template of the polymer PS film may be removed by heating in air at 45°C for 3 hours, or the film may be completely etched by dissolving it in chloroform.

Claims

1. A method for organizing building blocks into superparticles, wherein the method comprises the following steps: A step of adding a first solvent to a template of a patterned concave region in order to wet the surface of the concave region; The step of suspending the building block in a second solvent; The step of adding the second solvent to the template of the patterned concave region; The step of introducing a sweeping solvent onto the template by dropping, dripping, or washing in order to remove any excess second solvent from the surface of the template; Here, the first solvent and the second solvent are imperfectly miscible, and as a result, the surface tension at the interface between the first solvent and the second solvent is negligible; and, Here, the droplet of the second solvent diffuses the droplet of the first solvent within the concave region, thereby organizing the building blocks into superparticles within the concave region.

2. The method according to claim 1, wherein, due to the negligible interfacial surface tension between the first solvent and the second solvent, and the negligible Laplace pressure within the emulsified droplets of the first and second solvents, the emulsified droplets are prevented from becoming integrated and breaking apart without the need for an emulsifier.

3. Furthermore, the method according to claim 1, comprising the following steps: A step of suspending the building blocks by dispersing them using a combination of mechanical vibration and / or ultrasonic treatment.

4. The method according to claim 1, wherein the solubility of the second solvent in the first solvent is from 0.5% by weight to 35% by weight.

5. The method according to claim 1, wherein the building block is a solid particle, a polymer, a molecule, and / or an ion.

6. The method according to claim 1, wherein the building block has a size ranging from an atom to a micrometer.

7. Furthermore, the method according to claim 1, comprising the following steps: A step of adding the first solvent to the concave region on the template by dropping, dripping, or wetting.

8. The method according to claim 7, further comprising the following steps: The step of adding the second solvent together with building blocks suspended on a template of a patterned concave region by dropping, dripping, or wetting, wherein the volume of the second solvent added, including the suspended building blocks, is at least twice the volume of the first solvent remaining on the template.

9. The method according to claim 1, wherein the volume of the sweeping solvent introduced is at least five times the volume of the second solvent containing the suspended building blocks added to the template.

10. The method according to claim 1, wherein the sweeping solvent is the first solvent in a relatively pure form.

11. Furthermore, the method according to claim 1, comprising the following steps: A step of adjusting the size of superparticles in a concave region by changing the concentration of building blocks suspended in a second solvent and / or the size of the concave region.

12. The method according to claim 1, wherein the superparticles have a spherical structure, an elliptical structure, or a form of irregular arrangement of solid particles.

13. The method according to claim 1, wherein the first solvent is butanol or pentanol, and the second solvent is water.

14. The method according to claim 13, wherein the first solvent is 1-butanol.

15. The method according to claim 1, wherein the building block is SiO 2 Nanoparticles, Fe 3 O 4 Nanoparticles, polydopamine (PDA) nanoparticles, gold nanoparticles, CdTe quantum dots, FeOOH nanorods, and Fe 2 O 3 Select from the group consisting of nanodiscs.

16. The method according to claim 1, wherein the building block is a biopolymer, the biopolymer being chitosan, casein protein, fish sperm DNA, and / or living Micrococcus cells.

17. The method according to claim 1, wherein the building block is a micro-crystal of NaCl, Na 2 SO 3 micro-crystals, or Na 2 SO 4 micro-crystals thereof.

18. The method according to claim 1, wherein the patterned concave region is selected from the group consisting of cylindrical microporous arrays, cylindrical dimer microporous arrays, inverted pyramidal microporous arrays, cylindrical trimmer microporous arrays, tetramer microporous array films, and microporous arrays having irregular shapes.

19. Furthermore, the method according to claim 1, comprising the following steps: The step of adjusting the superparticles by applying an external stimulus while the droplets of the first solvent are diffusing with the second solvent.

20. The method according to claim 19, wherein the external stimulus is a magnetic field or an electric field.

21. Furthermore, the method according to claim 1, comprising the following steps: A step of using the ultraparticles in the nanoscale manufacturing of electronic displays, display panels, semiconductor devices, electronic devices, drug carriers, biosensors, and protein chips, for cell sorting applications, and / or as energy generation and storage materials.

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