Preparation of patterned anisotropic composite materials

Abstract

The present invention provides a method for forming a patterned anisotropic composite material, comprising inserting at least a portion of a heated probe into a matrix to induce a local phase change around the probe in the matrix, the matrix being a thermally reversible material and anisotropic filler matrix, and moving the heated probe in the matrix to form an aligned pattern of the anisotropic filler contained in the matrix. A patterned anisotropic composite material formed by the method is also provided.

Description

Technical Field

[0001] The present invention relates to the preparation of patterned anisotropic composite materials. Background Art

[0002] Materials composed of irreversibly arranged microscopic inorganic materials in composite structures have many applications, such as reinforced concrete, aerospace, turbines and bulletproof vests. However, the reconstruction of these materials is not simple and requires a series of energy-intensive industrial processes. As a result, these materials are eventually discarded, creating waste, which can lead to further environmental problems.

[0003] There are methods that can manipulate orientation, such as digital printing to create extensive 3D architectures, but these methods cannot achieve local spatial assembly of nano / microstructures. In addition, the assembly of nano / microstructures may not be preserved after digital printing, or even if this is successful, the alignment is unidirectional and global.

[0004] There is therefore a need for improved methods of ordering and / or manipulating materials. Summary of the invention

[0005] The present invention seeks to address these problems and / or to provide an improved method for preparing patterned anisotropic composite materials that allows for reversible manipulation of the ordering of the material.

[0006] According to a first aspect of the present invention, there is provided a method for preparing a patterned anisotropic composite material, the method comprising:

[0007] inserting at least a portion of the heated probe into a matrix to induce a local phase change around the probe within the matrix, wherein the matrix is ​​a thermoreversible material and an anisotropic filler matrix; and

[0008] The heated probe is moved within the matrix, thereby aligning the anisotropic fillers to form an aligned pattern of anisotropic fillers contained in the matrix.

[0009] In particular, the patterned anisotropy-containing composite material may be a reconfigurable patterned anisotropy-containing composite material.

[0010] The thermoreversible material may be any suitable material suitable for the purposes of the present invention. According to particular aspects, the thermoreversible material may include any suitable material. In particular, the thermoreversible material may include: a polymer, a polymer derivative, a hydrocarbon derivative, or a combination thereof. For example, the thermoreversible material may be selected from, but not limited to: an elastomer, a plastic, an organogel, an oleogel, a hydrogel, an aerogel, a metal organogel, a wax, or a combination thereof.

[0011] The anisotropic filler can be any suitable material suitable for the purposes of the present invention. According to particular aspects, the anisotropic filler can include one-dimensional (1-D) or two-dimensional (2-D) materials. For example, the anisotropic filler can include, but is not limited to: 1-D homogeneous structure, 1-D heterogeneous structure, 2-D structure or a combination thereof. In particular, the anisotropic filler can include, but is not limited to, rods, tubes, wires, fibers, sheets, thin layers of carbon-based metal-based, oxide-based, chalcogen-based, organic-based, polymer-based materials or a combination thereof.

[0012] The alignment pattern formed can be any suitable pattern. For example, the alignment pattern can be linear, non-linear, or a combination thereof. The alignment pattern can be controlled by adjusting: the size of the probe, the temperature at which the probe is heated, the speed at which the probe moves during movement, or a combination thereof.

[0013] According to another specific aspect, the method may further comprise:

[0014] removing the heated probe from the substrate; and

[0015] Cooling a patterned anisotropic composite material.

[0016] The method may further include forming the matrix prior to inserting, wherein the forming may include but is not limited to: placing the mixture of the thermoreversible material and the anisotropic filler in a mold, depositing and curing the mixture of the thermoreversible material and the anisotropic filler on a substrate, or 3-dimensionally (3D) printing an ink containing the mixture of the thermoreversible material and the anisotropic filler.

[0017] The method may further comprise reconfiguring the patterned anisotropy-containing composite material. In particular, reconfiguring the patterned anisotropy-containing composite material may comprise heating the composite material above its phase transition temperature.

[0018] According to a second aspect of the present invention, there is provided a patterned anisotropy-containing composite material formed by the method according to the first aspect. The patterned anisotropy-containing composite material may be a reconfigurable patterned anisotropy-containing composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order that the present invention may be fully understood and readily put into practice, exemplary embodiments will now be described by way of non-limiting example only, with reference to the accompanying illustrative drawings. In the drawings:

[0020] Figure 1 (a) shows a schematic diagram of a method according to an embodiment of the present application, Figure 1 (b) a top view showing how the movement of the probe aligns anisotropic fillers embedded in a matrix according to one embodiment of the present invention; and

[0021] Figure 2 Shown are cross-sectional alignments of the 3D stereotactic assemblies formed layer by layer during the sorting process. DETAILED DESCRIPTION

[0022] As noted above, there is a need for improved methods of preparing patterned anisotropic composite materials that allow for reversible manipulation of the ordering of the materials.

[0023] In general, the present invention relates to a method based on local phase transitions to confine changes in nano / micro material orientation to narrow convolutions. By programming different travel paths of the manipulator, the orientation of the nano / micro material can be changed, thereby generating any combination of piecewise linear and nonlinear anisotropy. This leads to the formation of a material system that can be finely controlled, including encoded nano / micro material orientations and having programming capabilities. In particular, the method of the present invention can be automated, thereby avoiding the process of manually manipulating and assembling nano / micro materials. In this way, the process is highly controllable, reliable and repeatable according to user specifications.

[0024] According to a first aspect of the present invention, there is provided a method for preparing a patterned anisotropic composite material, the method comprising:

[0025] inserting at least a portion of the heated probe into a matrix to induce a local phase change around the probe within the matrix, wherein the matrix is ​​a thermoreversible material and an anisotropic filler matrix; and

[0026] The heated probe is moved within the matrix, thereby aligning the anisotropic filler to form an aligned pattern of the anisotropic filler contained in the matrix.

[0027] The patterned anisotropy-containing composite material may be a reconfigurable patterned anisotropy-containing composite material, as described below.

[0028] The thermoreversible material may be any suitable material suitable for the purposes of the present invention. For the purposes of the present invention, a thermoreversible material may be defined as a material that reversibly changes between two phases. For example, a thermoreversible material may be a reversible material having a reversible sol-gel phase, a material that is reversible between a solid phase and a liquid phase, or a material that is reversible between a glassy state and a rubbery state by applying heat.

[0029] The thermoreversible material may include materials that are electrically conductive, optically active or inactive, mechanically responsive, magnetic, or a combination thereof. For example, if the thermoreversible material includes a magnetic material, applying a magnetic field will allow local magnetic domains of the magnetic material to align.

[0030] According to certain aspects, the thermoreversible material can be a polymer, a polymer derivative, a hydrocarbon derivative, or a combination thereof. For example, the polymer can be selected from, but not limited to, elastomers, plastics, organogels, oleogels, hydrogels, aerogels, metal-organogels, waxes, or a combination thereof. In particular, the thermoreversible material can be, but not limited to, ethylene-vinyl acetate, carrageenan hydrogels, paraffin waxes, or polyurethanes.

[0031] The anisotropic filler may be any suitable material. For the purposes of the present invention, an anisotropic filler may be a directionally dependent material consisting of an asymmetric crystalline or amorphous structure and whose directional properties depend on the orientation and alignment of the material structure.

[0032] Anisotropic fillers can be nanomaterials, micromaterials, or a combination thereof. Nanomaterials can be defined as materials having at least one nanoscale dimension. Similarly, micromaterials can be defined as materials having at least one microscale dimension.

[0033] According to certain aspects, the anisotropic filler may include a material that is a one-dimensional (1-D) or two-dimensional (2-D) material. In particular, the anisotropic filler may include a one-dimensional homogeneous structure, a one-dimensional heterogeneous structure, a two-dimensional structure, or a combination thereof.

[0034] The anisotropic filler may be any suitable material. For example, the anisotropic filler may be, but is not limited to, carbon-based, metal-based, oxide-based, chalcogen-based, organic-based, polymer-based, or a combination thereof. Metal-based anisotropic fillers may include transition metal-based anisotropic fillers. In particular, the anisotropic filler may include, but is not limited to, chalcogenides, carbon, graphene, graphene oxide, copper, silver, gold, cellulose, two-dimensional transition metal carbides, nitrides or carbonitrides (MXene), or a combination thereof.

[0035] The anisotropic filler can be any suitable form. For example, the anisotropic filler can be but not limited to the form of rod, wire, tube, sheet, fiber, layered structure, belt. In particular, the anisotropic filler can be but not limited to the form of nanorod, microrod, nanowire, microwire, nanotube, microtube, nanosheet, microsheet, nanofiber, microfiber, nanolayered structure, microlayered structure, nanobelt, microbelt, nanoparticle chain, microparticle chain or their combination. More specifically, the anisotropic filler can be but not limited to copper nanowire, carbon nanotube, silver nanowire, gold nanotube, cellulose nanofiber, graphene oxide nanosheet, molybdenum sulfide (MoS2) nanosheet or their combination.

[0036] The matrix can be a matrix of a thermoreversible material containing anisotropic fillers. For example, the matrix can be composed of a thermoreversible material as a matrix medium, and the matrix includes an anisotropic material as a filler. In particular, the anisotropic material can be embedded in the thermoreversible material. The matrix can have any suitable shape, size and geometry.

[0037] According to certain aspects, the method may further include forming a matrix before inserting. The matrix may be formed by any suitable method. Non-limiting examples of methods for forming the matrix include: arranging a mixture of a thermoreversible material and an anisotropic filler in a mold, depositing and curing the mixture of the thermoreversible material and the anisotropic filler on a substrate, or 3D (3D) printing an ink containing a mixture of a thermoreversible material and an anisotropic filler. In particular, the matrix may be spun, cast, molded, 3D printed or screen printed.

[0038] The probe used in the insertion can be any suitable probe. For example, the probe can be, but is not limited to, a needle, a rod, or a wire such as a solid needle or a tubular needle. The probe can include a sensor. Various sensors can be used for different functions. For example, when the probe is inserted into the matrix, the sensor can be used for in situ characterization within the matrix. The probe can be a heated probe. Therefore, the method can also include heating the probe before insertion. Heating can include heating the probe to a predetermined temperature. For example, the predetermined temperature can be any temperature suitable for causing a phase change in the thermoreversible material. According to specific aspects, the predetermined temperature can depend on the thermoreversible material contained in the matrix.

[0039] Heating can be carried out by any suitable means. For example, heating can be by heat conduction, or by a resistance wire or a suitable heating element.

[0040] Insertion can include inserting at least a portion of the heating probe into the matrix. In particular, insertion can include inserting at least a portion of one or more heating probes into the matrix. When multiple probes are inserted into the matrix, the speed and scalability of the method can be improved.

[0041] The insertion may induce a local phase change of the matrix near the probe, for example from a solid / gel / glass phase to a liquid / sol / rubber phase. In particular, the insertion results in an increase in local fluidity in the matrix near the probe. The advantage of such a local phase change is that the degree of phase change induced to the material can be better controlled. This also enables internal micro-defects within the matrix to be repaired locally and easily without disturbing any remaining non-defective areas.

[0042] The movement of the probe in the matrix can form any linear and / or nonlinear alignment pattern of the anisotropic material in the matrix. In particular, the movement of the probe in the matrix can generate a resistance that can align the anisotropic material in the matrix. In particular, the embedded anisotropic material can align in the direction of movement of the probe. Figure 1 (a) and 1(b) show an example of anisotropic packing alignment. According to certain aspects, the movement can be programmed to create arbitrary alignment patterns of linear and / or nonlinear anisotropy.

[0043] The alignment pattern formed can be any suitable pattern. According to certain aspects, the alignment pattern can be linear, non-linear, or a combination thereof. Examples of non-linear alignment patterns include, but are not limited to, concentric, azimuthal, radial, transverse, longitudinal, or a combination thereof. In particular, the alignment pattern can be a non-linear alignment pattern, thereby achieving non-linear optical and / or electro-optical properties.

[0044] The alignment pattern can be unidirectional, bidirectional, or multidirectional. In particular, the movement can enable the segmented alignment direction of anisotropic packings down to micrometer / nanometer resolution, thus achieving highly localized spatial ordering.

[0045] The alignment pattern can be controlled by adjusting: the size of the probe, the temperature at which the probe is heated, the speed at which the probe moves during movement, or a combination thereof. In particular, the scale and resolution of the alignment pattern can be adjusted based on the adjustment of the probe.

[0046] According to certain aspects, the alignment pattern can be controlled and / or modified based on in-situ measurements made by the probe after insertion and before movement. In particular, a sensor connected to the probe can be configured to make in-situ measurements, and the information can be fed back to a control unit, which can be configured to change the movement pattern of the probe so that a specific alignment pattern can be formed at a specific local area within the matrix.

[0047] The method may further include:

[0048] removing the heated probe from the substrate after removal; and

[0049] Cooling a patterned anisotropic composite material.

[0050] After removing the heated probe and cooling the patterned anisotropic composite material, the patterned alignment of the anisotropic filler formed during the movement may be in place. The cooling may be performed by any suitable means and may include cooling the anisotropic composite material to a predetermined temperature. The predetermined temperature may be any suitable temperature and may depend on the anisotropic filler and the thermoreversible material contained in the anisotropic composite material.

[0051] The method may also include reconstructing the patterned anisotropic composite material. The reconstruction may include reconstructing the alignment pattern of a portion of the patterned anisotropic composite material, or may include reconstructing the alignment pattern of the entire patterned anisotropic composite material. For example, the reconstruction may include erasing a portion or all of a previous alignment pattern of the patterned anisotropic composite material. The reconstruction may further include rewriting a portion or all of the previous alignment pattern after the erasure into a different alignment pattern. Alternatively, the reconstruction may include directly rewriting a portion or all of the previous alignment pattern into a different alignment pattern.

[0052] In particular, the reconfiguration may include heating the composite material to above its phase transition temperature. This may cause thermal reforming of the alignment pattern of the patterned anisotropic composite material. Even more specifically, the reconfiguration may include repeating the above-described insertion and movement. In this way, different alignment patterns may be formed in the patterned anisotropic composite material.

[0053] The method of the present invention enables user-defined local ordering of various functional anisotropic fillers embedded in a thermoreversible matrix. For example, a heated probe can be inserted into a thermoreversible matrix containing anisotropic fillers and moved in a first direction, thereby aligning the random configuration of the anisotropic fillers to the moving direction of the probe. The probe is then moved in a second direction in a segmented region of the matrix, rewriting the alignment of the anisotropic filler to the alignment of the second orientation. As a result, due to the different regional orientations of the anisotropic filler, different properties (for example, different degrees of transmittance in the case of optical materials) can be achieved in different regions. In addition, the main alignment pattern can be rewritten by introducing the probe into the matrix again. Since the whole process is reversible, different alignment patterns may rewrite the initial alignment pattern. The thermoreversibility of the matrix also allows the entire form, shape, and size of the composite material to be reshaped and changed into another structure by overall heating above the phase transition temperature. Therefore, the method of the present invention is able to reconstruct the form of the composite material as well as the volume anisotropic properties. In this way, the sustainable practice of recycling and upgrading cycles of reprogramming the material system to update the function can be achieved.

[0054] The method of the present invention can also form a three-dimensional (3D) segmented volume anisotropy in a single system. For example, the method of the present invention can be applied layer by layer in a composite material containing 3D anisotropy. In particular, a first layer of anisotropic composite material can be deposited or formed, and then the composite material containing anisotropy can be patterned according to the method of the present invention, i.e., by inserting a heated probe and moving the heated probe in the composite matrix. Subsequently, a second layer of anisotropic composite material can be deposited or formed, and then it is patterned like the first layer. The deposition or formation of each layer can be carried out by any suitable means. For example, the deposition or formation of each layer can be by 3D printing the layer. Alternatively, the layer in the composite material containing 3D anisotropy can be patterned by the method of the present invention, by lifting the probe to pattern a higher layer in the 3D material when the previous layer is patterned. In this way, it may not be necessary to deposit or form a new layer.

[0055] The alignment patterns of the first and second layers can be the same or different. Likewise, additional layers can be deposited or formed with the same or different alignment patterns. Furthermore, given the local phase change nature of the method, forming an alignment pattern for one layer does not affect the alignment pattern formed with respect to another layer, even if the layers are adjacent to each other. In this way, composite materials containing anisotropy having a 3D segmented alignment system can be formed that can be highly complex and easily customized. Figure 2 The example shows an example. Subsequently, if it is necessary to reconstruct the alignment pattern of each layer, thereby changing the properties of the composite material, the method of the present invention can be applied to each layer that needs to be reconstructed. This is also Figure 2 In particular, Figure 2 In the illustrated embodiment, it can be seen that the anisotropic pattern of the composite material has been restructured from an hourglass shape to a diamond geometry.

[0056] The advantage of the reconstruction aspect of the method of the present invention provides the ability of the method to be used in applications where a change in state or material properties is required. For example, an optical memory system using the method of the present invention can be configured to allow the encoding memory to be changed when necessary, as well as to be able to change the memory type. According to one embodiment, the method can achieve a change in memory type from 3D binary code to 2D multivariate code. The optical memory formed by the composite material containing anisotropy prepared by the method of the present invention is different from traditional memory in that it is soft, stretchable and almost always difficult to replicate anti-counterfeiting features with a unique spectrum, which is derived from the combination of aligned anisotropic fillers contained in the composite material. The reversible mechanical anisotropy of the material can also be achieved by changes in Young's modulus based on different alignment directions to adapt to new requirements. In addition, the recycling of broken or unwanted structures can be easily achieved by thermal reforming and applying the method of the present invention.

[0057] According to a second aspect of the present invention there is provided a patterned anisotropic comprising composite material formed by the method according to the first aspect.

[0058] In particular, the patterned anisotropic-containing composite material can be a reconfigurable patterned anisotropic-containing composite material. For example, the material can be reconfigured to erase part or all of a previous alignment pattern of the patterned anisotropic-containing composite material. Reconfiguration can include overwriting part or all of a previous alignment pattern of the patterned anisotropic-containing composite material.

[0059] The patterned composite material containing anisotropy formed can have the properties described above for the patterned composite material containing anisotropy formed by the method of the first aspect. The patterned composite material containing anisotropy formed can have many applications, such as in the field where highly complex structures or customized materials are required. Other application fields in which the patterned composite material containing anisotropy of the present invention can be used include, but are not limited to, nonlinear optics or electro-optics for lasers, interactions with materials, displays, sensors, actuators, information and storage technology, mechanical construction, robotics and electronic products.

[0060] While the foregoing description has described exemplary embodiments, those skilled in the art will appreciate that many changes can be made without departing from the invention.

Claims

1. A method for preparing a patterned anisotropic composite material, the method comprising: inserting at least a portion of the heated probe into a matrix to induce a local phase change around the probe within the matrix, wherein the matrix is ​​a thermoreversible material and an anisotropic filler matrix; and The heated probe is moved within the matrix to align the anisotropic filler to form an aligned pattern of the anisotropic filler contained in the matrix, the aligned pattern comprising nanomaterial and / or micromaterial orientation within narrow convolutions, wherein the aligned pattern is controlled by adjusting: the size of the probe, the temperature at which the probe is heated, the speed at which the probe moves during movement, or a combination thereof.

2. The method according to claim 1, further comprising: removing the heated probe from the matrix; and Cooling a patterned anisotropic composite material.

3. The method according to claim 1, wherein: The patterned anisotropy-containing composite material is a reconfigurable patterned anisotropy-containing composite material.

4. The method according to claim 1, wherein: The thermoreversible material includes: a polymer, a polymer derivative, a hydrocarbon derivative or a combination thereof.

5. The method according to claim 1, wherein: The thermoreversible material is selected from the group consisting of: elastomers, plastics, organogels, oleogels, hydrogels, aerogels, metal organogels, waxes, or combinations thereof.

6. The method according to claim 1, wherein: The anisotropic filler includes a one-dimensional (1-D) or two-dimensional (2-D) material.

7. The method according to claim 6, wherein: The anisotropic filler includes: a 1-D homogeneous structure, a 1-D heterogeneous structure, a 2-D structure or a combination thereof.

8. The method according to claim 1, wherein: The anisotropic filler includes: rods, tubes, wires, fibers, sheets, layered structures of carbon-based, metal-based, oxide-based, chalcogen-based, organic-based, polymer-based materials or combinations thereof.

9. The method according to claim 1, wherein: The alignment pattern is linear, non-linear, or a combination thereof.

10. The method of claim 1, further comprising forming the matrix prior to the inserting, wherein The forming includes: placing a mixture of the thermoreversible material and the anisotropic filler in a mold, depositing and curing the mixture of the thermoreversible material and the anisotropic filler on a substrate, or 3D printing an ink containing the mixture of the thermoreversible material and the anisotropic filler.

11. The method of claim 1, further comprising reconstructing the patterned anisotropic-containing composite material.

12. The method according to claim 11, wherein: The reconfiguring the patterned anisotropic composite material comprises heating the composite material above its phase transition temperature.

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