TW201934626A - Method for producing three-dimensional ordered porous microstructure and monolithic column produced thereby - Google Patents

Abstract

The present invention relates to methods for producing a three-dimensional ordered porous microstructure. In the procedure where a three-dimensional ordered microstructure is produced using a colloidal crystal templating process, the particles in the three-dimensional ordered microstructure is subjected to deformation, so as to effectively increase the contact between orderly arranged particles while removing the solvent used to suspend the particles. The invention further relates to a monolithic column produced thereby. Compared to the monolithic columns produced by conventional methods, the monolithic column according to the invention is characterized in having a higher aspect ratio and a higher pore regularity, while the connecting pores in the column are relatively large in pore size.

Description

Manufacturing method of three-dimensional ordered porous microstructure and integral column made by the method

The invention relates to a method for manufacturing a three-dimensional ordered porous microstructure. The invention also relates to a three-dimensional ordered porous microstructure with a high thickness made by the manufacturing method, especially an integral column with a high aspect ratio.

If the pores in the porous material have a pore diameter close to the wavelength of light and have a high order of arrangement, the porous material may have special and highly practical optical properties and can be widely used in photocatalysis, biological carriers, adsorption, filtration, Insulation, chromatographic separations, semiconductors and micro-induction.

The basic structure of ordered porous microstructures is composed of a medium with periodic arrangement in one, two, or three dimensions. The one-dimensional structure is the so-called optical multilayer film, which is widely used in optical lenses. The one-dimensional photon energy gap is caused by the periodically arranged multi-layer dielectric film, so that photons in certain wavebands cannot pass through, achieving high-efficiency reflection. The two-dimensional and three-dimensional periodic array structure is the most ordered porous microstructure.

It is known that three-dimensional ordered porous microstructures can be manufactured in a self-assembly mode, which mainly uses particles of uniform size such as polystyrene, polymethyl methacrylate, or silicon dioxide, and uses natural gravity sedimentation, centrifugation, and vacuum The method of suction filtration and other methods will self-assemble particles on a substrate to form a three-dimensional ordered microstructure, and then use a substrate with a three-dimensional ordered microstructure on the surface as a template. An inorganic oxane monomer is added to the template to make a sol. The gel reacts to form an inverse structure. Finally, the template is removed by calcination and extraction to generate a three-dimensional ordered porous microstructure with photonic crystal properties. The process is generally referred to as colloidal crystal templating, and has been disclosed in, for example, U.S. Patent No. 6414043 and PRC Patent Publication No. 104976925A1.

The Republic of China Patent No. I558866 discloses a method for making a three-dimensional ordered microstructure, which involves applying a shaping electric field to drive particles into a self-assembling process, thereby forming a hexagonal densely packed particle structure. The method disclosed in Patent Cooperation Treaty Publication No. WO2017080496A1 involves self-assembling particles to form the most densely packed three-dimensional ordered microstructures on a substrate, and constructing a sacrificial layer between the three-dimensional ordered microstructures and the substrate to make three-dimensional The ordered porous microstructure can maintain the structural integrity when detached from the substrate.

Although a large-area three-dimensional ordered porous microstructure has been successfully manufactured using the above-mentioned technology, the thickness of the microstructure is still unsatisfactory. In the process of constructing a three-dimensional ordered microstructure, at least a part of the particles are arranged in the form of the densest packing, where each particle is tangent to the adjacent 12 particles. When the particle is a hard sphere, the contact between the particle and an adjacent particle is theoretically only one point. Moreover, since the particles used cannot be completely uniform in particle size, some adjacent particles do not even have contact at all. As the thickness of the three-dimensional ordered microstructures increases, the lack of contact area between particles can easily lead to low structural strength. In particular, before using a three-dimensional ordered microstructure as a template to make an inverse structure, a heating process is usually performed to remove the solvent. In this heating process, the rapidly volatile solvent after heating easily destroys the already fragile stencil, which causes the stencil to crack, resulting in a low yield of anti-structure fabrication.

In theory, a three-dimensional ordered porous microstructure with a high aspect ratio is based on its regular internal skeleton network and periodic pore structure, which is very suitable as a monolithic column for the layer of matter Analytical separation. However, the current manufacturing process not only takes several days, it is difficult to reach the scale of mass production, and the stencil structure is generally loose in the arrangement of particles, which leads to the poor continuity of the three-dimensional ordered porous microstructure products that are subsequently completed. The aspect ratio is also limited. In addition, hard spheres are used in the current colloidal crystal stencil manufacturing process. Because the contact area between adjacent particles in the stencil is very small, the communication holes between large holes in the manufactured inverse structure will be too small, resulting in an overall column. There are problems with low mass transfer rates and excessive back pressure. To use colloidal crystal stencils to make monolithic columns, one must also face the time-consuming and inefficient stencil removal process. These problems severely reduce the manufacturing yield of the monolithic column and its commercial application potential.

Therefore, the industry still has a strong demand for making three-dimensional ordered microstructures with high thickness and using them as templates to produce three-dimensional ordered porous microstructures.

Now, the inventors of the present invention have unexpectedly discovered that in the process of using a colloidal crystal stencil to make a three-dimensional ordered microstructure, after the particles have completed self-assembly, the particles can be deformed, such as heating and pressing the particles. And dissolve it. This process of deforming particles can not only effectively improve the contact between the ordered particles, but also remove the solvent for suspended particles from the three-dimensional ordered microstructure, and also make the rapidly volatilizing solvent not substantially destroy the three-dimensional when heated. Ordered microstructure. More importantly, the three-dimensional ordered microstructure is used as a monolithic column made of a template. The communication holes in the column have a larger pore size than the communication holes formed by conventional methods, and have high mass transfer efficiency. And the advantage of low string back pressure. Accordingly, the present invention solves the aforementioned problems in the prior art.

According to a first aspect of the present invention, there is provided a method for manufacturing a three-dimensional ordered porous microstructure, characterized in that the method includes the following steps: A. forming a three-dimensional ordered microstructure composed of a plurality of substantially spherical particles , So that there are multiple gaps between the plurality of particles; B. deform substantially spherical particles in the three-dimensional ordered microstructure, so that the particles are deformed to have a longest radius R and a shortest radius r Where the ratio of r / R is greater than / 2 but less than 1; C. filling an anti-structure material into the void; and D. removing the three-dimensional ordered microstructure to obtain the three-dimensional ordered porous microstructure.

In a preferred embodiment, step B includes heating the three-dimensional ordered microstructure to soften the plurality of particles and cause deformation. In a more preferred embodiment, the particles have a glass transition temperature, and the step B, in comparison to a high temperature of the glass transition temperature of about 0 to 20 ^o C, and The The three-dimensional ordered microstructure heating is described. In another more preferred specific embodiment, the particles have a glass transition temperature, and the step B, is compared to a low temperature of the glass transition temperature of about 1 to 15 ^o C will The three-dimensional ordered microstructure is heated. In a more preferred embodiment, the step of heating, in a lower temperature compared to the glass transition temperature of from about 3 to 15 ^o C, and the heated three-dimensionally ordered microstructure. In a more preferred embodiment, at a lower temperature compared to the glass transition temperature of from about 3 to 10 ^o C, and the heated three-dimensionally ordered microstructure.

In another preferred embodiment, step B includes applying pressure to the three-dimensional ordered microstructure to cause the plurality of particles to squeeze each other to deform.

In another preferred embodiment, step B includes immersing the three-dimensional ordered microstructure in a solvent capable of dissolving the plurality of particles, so that the plurality of particles swell and deform.

In a preferred embodiment, the particles are homogeneous spheres made of a single type of polymer homopolymer or copolymer, and the glass transition temperature is the overall glass transition temperature of the particles. In another preferred embodiment, the particles have a core-shell structure, each particle has a core and a shell covering the core, and the core and the shell are respectively made of different polymer materials, and The glass transition temperature is a glass transition temperature of the housing.

In a preferred embodiment, the step of forming a three-dimensional ordered microstructure includes dispersing the plurality of particles in a solvent to form a suspension, and allowing the plurality of particles to self-assemble to form the Three-dimensional ordered microstructure.

In a preferred embodiment, the step of heating includes heating the three-dimensional ordered microstructures for a period of time to soften the plurality of particles and remove the solvent.

According to the above technical features, at least a part of the particles in the three-dimensional ordered microstructure are arranged in the most densely packed form.

In a preferred embodiment, the step of removing the three-dimensional ordered microstructure includes removing the three-dimensional structure by using a method selected from the group consisting of Soxhlet extraction and supercritical fluid extraction. Ordered microstructure.

The manufacturing method of the three-dimensional ordered porous microstructure described above is suitable for making a three-dimensional ordered porous microstructure with a high thickness, and is particularly suitable for making a monolithic column with a high aspect ratio. Moreover, compared with the monolithic column made by the conventional manufacturing process, the monolithic column of the present application has the structural characteristics of high aspect ratio, regularity of high pores, and large pore diameter of the connecting holes.

Therefore, according to a second aspect of the present invention, there is provided a monolithic column made by the above-mentioned method for manufacturing a three-dimensional ordered porous microstructure.

According to the third-party manufacturer's aspect of the present invention, it also provides a monolithic column, which includes: a plurality of spherical macropores in an orderly arrangement, a uniform diameter between 100 nanometers and 6 micrometers, and a plurality of communication holes connecting the macropores. Has a uniform diameter between 10 nanometers and 3 micrometers, wherein at least 70% of the macropores are arranged in the most densely packed form, and the macropores have a longest radius R and a shortest radius r, where The ratio of r / R is less than or equal to 0.99.

In a preferred embodiment, at least 80% of the macropores are arranged in the most densely packed form. In a more preferred embodiment, at least 90% of the macropores are arranged in the most densely packed form. In a most preferred embodiment, at least 95% of the macropores are arranged in the most densely packed form.

In a preferred embodiment, the r / R ratio is less than or equal to 0.98. In a more preferred embodiment, the r / R ratio is less than or equal to 0.96. In a most preferred embodiment, the r / R ratio is less than or equal to 0.94.

In a preferred embodiment, the monolithic column has a height of at least 1 cm and an aspect ratio of not less than 1.

The purpose, features and advantages of the present invention will be described in detail through embodiments with reference to the accompanying drawings.

Unless otherwise stated, the following terms used in the specification and scope of the patent application have the definitions given below. Please note that the use of the singular word "a" in the specification and scope of the patent application is intended to cover one or more of the matters contained in it, such as at least one, at least two, or at least three, rather than implying merely to have A single item. In addition, open-ended conjunctions such as "including" and "having" used in the scope of a patent application indicate a combination of elements or components described in a claim, and do not exclude other components or components not specified in the claim. It should also be noted that the term "or" generally includes "and / or" in the sense, unless the content clearly indicates otherwise. The terms "about" or "substantially" used in the specification of this application and the scope of the patent application are used to modify any slightly variable errors, but such slight changes will not change its essence.

The invention mainly provides a method for manufacturing a three-dimensional ordered porous microstructure, which is suitable for manufacturing a three-dimensional ordered porous microstructure having a high thickness, and is particularly suitable for manufacturing a monolithic column having a high aspect ratio. As shown in FIG. 1, the manufacturing method of the three-dimensional ordered porous microstructure includes: A. forming a three-dimensional ordered microstructure composed of a plurality of substantially spherical particles, so that the plurality of particles have a large number of each other B. deform the substantially spherical particles in the three-dimensional ordered microstructure, so that the particles are deformed to have a longest radius R and a shortest radius r, where the ratio r / R is greater than / 2 but less than 1; C. filling an anti-structure material into the void; and D. removing the three-dimensional ordered microstructure to obtain the three-dimensional ordered porous microstructure.

The three-dimensional ordered microstructure refers to a microstructure obtained by subjecting particles to an ordered three-dimensional arrangement. The "ordered" means that the distances between particles are regular, and it is preferable that the distances between particles are approximately equal. The particles that make up this microstructure usually have a uniform particle size, shape, chemical composition, internal structure, or surface properties to facilitate non-covalent interactions between the particles, and thus spontaneously arrange into a regular structure similar to a crystal lattice. In a preferred embodiment, the particles are monodisperse substantially spherical particles with a uniform particle size, and more preferably have a particle size ranging from 1 nanometer to 1000 micrometers, such as 100 nanometers to 6 micrometers.

At least a part of the particles in the three-dimensional ordered microstructure are arranged in the most densely packed form, that is, adjacent particles are tangent to each other, and the center of any three tangent particles forms an equilateral triangle. Each particle has a coordination number of 12, and a plurality of approximately triangular spaces are left between the particles. More preferably, at least a part of the particles in the three-dimensional ordered microstructure is in the form of three-dimensional hexagonal closest packing (hcp), three-dimensional face centered cubic packing (fcc), or a combination thereof. arrangement. The inverse structure produced by using the three-dimensional ordered microstructure as a template is the three-dimensional ordered microstructure.

The three-dimensional ordered microstructure can be formed through self-assembly of particles. The term "self-assembly" used in this specification refers to the aggregation of micro- or nano-scale particles into a three-dimensional ordered microstructure in response to conditions in the external environment, and in particular, van der Waals ' force), π-π interaction, hydrogen bonding, and other non-covalent interactions, thereby spontaneously forming the three-dimensional ordered microstructure under near-thermodynamic equilibrium conditions.

Non-limiting examples of materials from which these particles are made include polymer materials, inorganic materials, metals, and the like. The polymer material is preferably a thermoplastic polymer material. Examples of the polymer material include, but are not limited to, polymer homopolymers such as polystyrene (PS), polymethyl methacrylate (PMMA), polybutyl methacrylate ( (PBMA), polymethyl acrylate, polyethyl acrylate (PEA), polybutyl acrylate (PBA), polybenzyl methacrylate, polyα-methylstyrene, polyphenylmethacrylate, polymethyl Diphenyl acrylate and polycyclohexyl methacrylate; and high molecular copolymers such as styrene-acrylonitrile copolymer, styrene-methyl methacrylate copolymer, styrene-butyl methacrylate copolymer And styrene-butyl acrylate copolymer. Examples of inorganic materials include, but are not limited to, titanium oxide, zinc oxide, cerium oxide, tin oxide, hafnium oxide, barium oxide, aluminum oxide, yttrium oxide, zirconia, copper oxide, nickel oxide, and silicon oxide. Examples of metal materials include, but are not limited to, gold, silver, copper, platinum, aluminum, zinc, cerium, hafnium, barium, yttrium, zirconium, tin, titanium, cadmium, and iron, and alloys thereof.

In a preferred embodiment, the particles used are made of a polymer material, and more preferably, the particles used are made of a monomer selected from styrene monomers, methacrylate monomers, and acrylates. Homopolymer or copolymer made from monomer polymerization. In a specific embodiment, the particles used are homogeneous spheres made of a single type of polymer homopolymer or copolymer. In another embodiment, the particles used have a core-shell architecture. The “core-shell structure” referred to in the present application means that each particle has a core and a shell covering the core, and the core and the shell are made of different polymer materials, respectively. The manufacturing method of the above micron or nanometer particles belongs to the prior art. For example, when the particles used are polystyrene particles, they can be synthesized by an emulsifier-free emulsification polymerization method to make polystyrene spherical particles with a particle diameter of hundreds of nanometers. When it is desired to form particles with a core-shell structure, the emulsifier polymerization method without an emulsifier can be similarly used. The first monomer is first polymerized for a period of time to form a core, and then the second monomer is added to form the first monomer. A shell made of a copolymer of this species and a second monomer.

In step A where a three-dimensional ordered microstructure is formed, a suspension may be first prepared, which contains a plurality of uniformly dispersed colloidal spherical particles. For example, when the particles used are polystyrene homopolymer or copolymer particles, the particles can be uniformly dispersed in a solvent to form a suspension. A suitable solvent is any known solvent capable of achieving the above-mentioned purpose of uniformly dispersing particles without causing substantial chemical reaction with the particles or other ingredients in the manufacturing process, which may be organic solutions or aqueous solutions, including but not limited to water and C _{1- 6 Alcohols are} preferably water, methanol, ethanol, and aqueous solutions thereof. One of the methods, such as natural gravity sedimentation, centrifugation, vacuum pumping, or electrophoresis, can be used to drive the particles to self-assemble to form a three-dimensional ordered microstructure in which the plurality of particles are densely packed. In a preferred embodiment, the suspension is placed in a long tubular mold so as to form a three-dimensional ordered microstructure with a high aspect ratio, so that the three-dimensional ordered microstructure is then used as a template to produce a high depth to width Ratio of three-dimensional ordered porous microstructures.

The inventors of the present application have discovered that when the three-dimensional ordered microstructure is given a chemical or physical treatment to deform the particles located therein, adjacent particles in the three-dimensional ordered microstructure will deform each other to cause each other due to the deformation. The increased contact area between them results in a three-dimensional ordered microstructure with a more compact structure. The term "deformation" as used in this specification encompasses any chemical or physical treatment capable of substantially changing the shape of particles in a three-dimensional ordered microstructure. In a specific embodiment using substantially spherical particles, the shape of these particles before being deformed is close to the true sphere, and after undergoing chemical or physical treatment, the particles deform and come into contact with adjacent particles. A longest radius R and a shortest radius r, where the ratio r / R is greater than / 2 but less than 1. Applicable processing steps may be selected depending on the material of the particles, including, but not limited to, heating, pressing, dissolving, and the like.

In a preferred embodiment, step B includes heating the three-dimensional ordered microstructure to soften the plurality of particles and cause deformation. The term "softening" as used in this application refers to the orderly arrangement of particles that deform under the action of heat and then stick to each other. Particle softening can be observed and measured under an electron microscope. Figure 2 shows unheated softened polystyrene spherical particles with a shape close to a true sphere. Figure 3 shows that the polystyrene particles arranged in the most densely packed form softened by heating and began to deform. At this time, the contact area between each particle and an adjacent particle increases. Taking softened spherical particles as an example, the ratio of the shortest radius r to the longest radius R will be greater than / 2 but less than 1, i.e. . For example, the r / R ratio of the particles shown in FIG. 3 is about 0.94. The size of the contact area between adjacent particles in the three-dimensional ordered microstructure is related to the size of the connected pores between the giant pores in the three-dimensional ordered porous microstructure made subsequently. In other words, the smaller the r / R ratio, the larger the pore diameter of the connected pores relative to the size of the macropores in the three-dimensional ordered porous microstructure made in this application, and the pore diameter of the connected pores is approximately equal to 2r / . In a preferred embodiment, the r / R is less than or equal to 0.99, preferably less than or equal to 0.98, more preferably less than or equal to 0.96, such as less than or equal to 0.94. Non-spherical particles, such as oval particles, also tend to decrease in r / R ratio as they soften under heat. Figure 4 shows that polystyrene spherical particles are deformed by heat for a long time, causing each particle to be completely in close contact with the adjacent six particles, without pores between them, forming an approximately regular hexagonal configuration, which cannot be used as Anti-structure template. Therefore, in the present application, the degree of softening of the particles can be controlled by adjusting the temperature and / or time of heating so that appropriate pores remain between the particles.

As is familiar to those with ordinary knowledge in the relevant technical field, when the micro- or nano-scale particles used in this application are made of crystalline materials, they will begin to melt at a temperature above the melting point. When the micro- or nano-scale particles used in the present application are made of an amorphous material, they may have a glass transition temperature. The term "glass transition temperature" or abbreviated " _Tg " as used in this application means that the material constituting the particles changes from a glassy state with its rigid and brittle characteristics to a soft and flexible rubbery state (rubbery state). The glass transition temperature can be measured according to ASTM-E1356 using differential scanning calorimetry. It is known that the T _{g of a} polymer material can be changed by copolymerizing other monomers, changing the degree of branching, adjusting the chain length, adjusting the degree of cross-linking, and adding a plasticizer. For example, the T _g of commercially available styrene homopolymer sphere particles is about 105 ^° C. As shown in Examples 1 to 6 below, by copolymerizing different monomers with styrene, the T _{g of} polystyrene sphere particles can be effectively reduced.

Known in the prior art, spherical particles at a temperature above its T _g will exhibit rubbery melted deformed, hard sphere form at temperatures below its T _g of the presentation will be. Accordingly, the heating step B is a preferred embodiment, the particles are in a higher temperature as compared to its glass transition temperature from about 0 to 20 ^o C, the heating period of time, so that the particles soften. Since the particles will rapidly deform in their rubbery state, the heating time is usually short, such as in the range of seconds to minutes. It is preferred to use particles with a large particle size, such as particles with a particle size greater than 1 micron, to avoid excessive particle deformation. After heating, the temperature can be lowered to a lower temperature T _g as compared to the particles, the particles return to its glassy state, and utilizes volatile at this temperature, vacuum exhaust, etc. for removal of suspended particles in step A Solvent.

The inventors of the present application have unexpectedly found that after heat-treating the particles at a temperature about 1 to 15 ^o C lower than their glass transition temperature for a period of time, the particles will appear although they will not be converted to their rubbery state. The phenomenon of softening. While not wishing to be bound by theory, the inventors believe the present application, a material constituting the particles at a temperature close to its T _g, wherein the molecule will receive enough energy to start to flow, resulting in a slight softening particles. In a specific embodiment where the particles used are homogeneous spheres made of a single type of polymer homopolymer or copolymer, the glass transition temperature refers to the bulk glass transition temperature (bulk T _g ) of the particles. In a specific embodiment in which the particles used have a core-shell structure, the core of the particles may be made of a homopolymer of a certain monomer (for example, styrene), and the shell thereof may be made of the monomer and another monomer ( Such as butyl methacrylate). In this case, the glass transition temperature T _g refers to housing, which may be lower than the core T _g, so that the core than in the above temperature range to soften more easily.

Accordingly, in another preferred embodiment of the heating step B, the particle is at a low temperature of the glass transition temperature of about 1 to 15 ^o C at the comparison thereof, it is preferably in the particle compared to a T _g of At a temperature that is about 3 to 10 ^o C lower, for example, at a temperature that is about 3 to 5 ^o C lower than the T _{g of the} particles, heat for a period of time to soften the particles, preferably simultaneously removed in step A. Solvent for suspended particles. In order to prevent the solvent from flowing too fast and destroying the three-dimensional ordered microstructure, the heating temperature is preferably selected to a temperature that is substantially lower than the boiling point of the solvent but can allow the solvent to evaporate effectively. In a specific embodiment using water or a C _{1-6 alcohol} , such as water, methanol, ethanol, or an aqueous solution thereof, as a solvent, the solvent used is preferably used for constructing a three-dimensional ordered microstructure because of its low boiling point. The particle is a particle having a low T _g so that in step B, a heating temperature capable of simultaneously softening the particles and removing the solvent is selected. In a preferred embodiment, the _Tg of the particles is in the range of 0 ^o C to 100 ^o C, more preferably in the range of 50 ^o C to 95 ^o C, and most preferably in the range of 60 ^o C to 90 ^In the range of ^o C, for example in the range of 75 ^o C to 85 ^o C. The heating time is not particularly limited as long as the purpose of softening the particles and removing the solvent is achieved. Generally, the lower the heating temperature, the longer the heating time must be in order to achieve the above purpose. The heating time may be several minutes to several days, and preferably several tens of minutes to one day to achieve mass production.

In another preferred embodiment, step B includes applying pressure to the three-dimensional ordered microstructure to cause the plurality of particles to squeeze each other to deform. The process of applying pressure includes, but is not limited to, centrifugation, vacuum evacuation, etc. to apply pressure to the particles in the same direction (for example, 5,000 psi or more). Subsequently, the solvent used for the suspended particles in step A is removed by means of volatilization and vacuum evacuation. In this specific embodiment, it is preferable that the particles have a core-shell structure, in which the outer shell is softer and the core is harder, so that when the particles are pressed against each other due to pressure, the soft outer shell is deformed, causing contact between the particles. Area increases and r / R ratio falls between In the range of / 2 to 1.

In another preferred embodiment, step B includes immersing the three-dimensional ordered microstructure in a solvent capable of dissolving the plurality of particles, so that the plurality of particles swell and deform. Preferably, before performing step B, the solvent used for suspending particles in step A is removed in advance by means of volatilization and vacuum extraction. In a specific embodiment where the particles used are made of a polymer material, it is preferred that the solvent is an organic solvent, and more preferably a solvent system obtained by mixing an organic solvent with water to appropriately reduce the solubility of the particles . In a specific embodiment where the particles are homopolymers or copolymers polymerized from styrene monomers, the solvent includes, but is not limited to, styrene, toluene, chlorocyclohexane, and mixtures thereof with water. In a specific embodiment in which the particles are homopolymers or copolymers polymerized from methacrylate monomers, the solvent includes, but is not limited to, C _{1-4 alcohols} , 1,4-dioxane , Benzene, n-hexane and their mixtures with water. Organic solvents such as acetone, methyl ethyl ketone, dimethylformamide, ethyl acetate, and mixtures thereof with water can also be used. When the three-dimensional ordered microstructure is immersed in a solvent, the molecular chains on the surface of the particles will begin to loosen due to contact with the solvent, causing some micro-swelling of the particles, resulting in an increase in the contact area between the particles and the r / R ratio Fall on In the range of / 2 to 1. The contact area between particles can be adjusted by adjusting the soaking time and / or the soaking temperature.

In step C of filling the voids, the three-dimensional ordered microstructure voids are filled with the anti-structure material. Anti-structural materials include, but are not limited to: metals, such as gold, silver, copper, nickel, platinum, nickel-tungsten alloys, etc .; oxides, such as zinc oxide, silicon dioxide, cuprous oxide, etc .; and polymer materials, such as polybenzene Ethylene, polyacrylates, polymethacrylates, acrylamides, polypyrrole, polyethylene, polypropylene, polyvinyl chloride, silicone, etc. In a specific embodiment for manufacturing a monolithic column, it is preferred that the anti-structure material is selected from polymer hydrogels, which are composed of acrylamide, acrylates, methacrylates, Polymerized by hydrophilic monomers such as siloxanes. Preferred polymer hydrogels include poly (hydroxyethyl methacrylate) (PHEMA), polyglycidyl methacrylate (PGMA), polydimethylsiloxane (PDMS), polypropylacrylamide and their derivatives Thing. The anti-structure material can be filled by centrifugation, vacuum pumping, pressure extrusion, sputtering, electroplating, chemical vapor deposition, atomic layer deposition, etc. In a specific embodiment in which the anti-structure material is a polymer material, a monomer or a precursor constituting the polymer material may be first filled into a gap, and then it may be cured and shaped.

In the step of removing the three-dimensional ordered microstructure, particles in the three-dimensional ordered microstructure are removed after the anti-structural material is shaped. The removal method is known in the prior art, and includes but is not limited to a chemical removal method, a high temperature removal method, and the like. For example, in the conventional chemical removal method, a chemical reagent capable of dissolving particles such as toluene, acetone, ethyl acetate, hydrofluoric acid, sodium hydroxide, etc. can be used to treat the film-type microstructure, and the particles can be separated from the inverse structure. material. However, when conventional processes such as immersion or extraction are used to process microstructures with high aspect ratios, the problem of difficult to remove stencils will occur. In addition, the anti-structural material used in making the monolithic column is a polymer material that cannot withstand high temperatures, so it is not suitable to remove the stencil by a high temperature removal method.

The inventors of the present application have unexpectedly discovered that the use of Soxhlet extraction or supercritical fluid extraction can overcome the problem of difficult to remove stencils due to the high aspect ratio of microstructures. Accordingly, in a preferred embodiment of the present application, the three-dimensional ordered microstructure is removed by a method selected from the group consisting of a Soxhlet extraction method and a supercritical fluid extraction method. The term “Soxhlet extraction method” used in the present application means that the microstructure is placed in a Soxhlet extractor, and the solvent used to dissolve the stencil is heated and refluxed to continuously extract the stencil material from the microstructure. Generally, the temperature used by the Soxhlet extraction method is higher than the boiling point of the solvent used to dissolve the stencil, and the extraction time lasts about 3-7 days. The term "supercritical fluid extraction method" used in the present application means that the supercritical fluid is used to dissolve the stencil material under the conditions above the critical temperature and critical pressure, and then the pressure is reduced or the temperature is increased to dissolve the Precipitation of stencil material in critical fluid. In a preferred embodiment, CO _{2 is used} as a supercritical fluid, and co-solvents such as acetone, toluene, or ethyl acetate are used to remove polystyrene-based stencil materials.

The three-dimensional ordered porous microstructures made according to the method of the present application can be subjected to additional processing processes to manufacture various commercial products. In a preferred embodiment, the three-dimensional ordered porous microstructure can be subjected to conventional procedures such as cutting, packaging, and / or undergoing chemical modification to have a suitable surface functionality to form a monolithic column for use as Chromatographic separation of stationary phase materials. The “monolithic column” referred to in the present application includes a continuous medium composed of the aforementioned anti-structural material, which forms a number of ordered spherical macropores, has a uniform diameter between 100 nanometers and 6 micrometers, and several interconnected The pores of the macropores have a uniform diameter between 10 nanometers and 3 micrometers. In a preferred embodiment, the spherical macropores are arranged in the most densely packed form. In this case, each macropore can communicate with an adjacent macropore via 12 communicating holes. The monolithic column preferably has at least 70% of macropores, more preferably at least 80% of macropores, and most preferably at least 90% of macropores, such as at least 95% of macropores, in the most densely packed form. arrangement. The proportional relationship between the longest radius R and the shortest radius r of a giant hole can be expressed by an inequality To represent. The smaller the r / R ratio, the larger the pore diameter of the connected pores relative to the size of the macropores in the three-dimensional ordered porous microstructure. The pore diameter of the connected pores is approximately equal to 2r / . In a preferred embodiment, the communication hole in the column has a large pore diameter, that is, the r / R is less than or equal to 0.99, preferably less than or equal to 0.98, more preferably less than or equal to 0.96, such as less than or equal to 0.94. The monolithic column may further include a hollow pipe body, which may be made of materials such as stainless steel, quartz, or glass, and has an inner wall for the continuous medium to adhere. In a preferred embodiment, the monolithic column has a height of at least 1 cm, such as a height of at least 3 cm or at least 5 cm, and has an aspect ratio of not less than 1, such as not less than 2.5 or not less than Aspect ratio of 3. The "aspect ratio" as used herein means the ratio of the column height to the diameter of the monolithic column.

The following examples are provided only to illustrate the present invention and not to limit the scope of the present invention.

Example 1 : Preparation of polystyrene - butyl methacrylate nanospheres <br/> A butyl methacrylate monomer solution was added to a styrene monomer solution (99.6 parts by weight), and the system solid content was formulated into 10% by weight. The mixture was stirred at 350 rpm for 1 hour, and the temperature was maintained at 65 ° C. Next, 0.25 g of potassium sulfate was added to the mixture to start the polymerization reaction. After 16 hours, the monomer was completely consumed. In the present embodiment, by the amount of the butyl methacrylate solution was controlled to 10 to 30 ml, the glass transition temperature can be adjusted within the polystyrene particles located at 82 ^o C to 26 ^o C range.

Example 2 : Preparation of polystyrene - butyl acrylate nanospheres <br/> A butyl acrylate monomer solution was added to a styrene monomer solution (99.6 parts by weight), and the system solid content was formulated to 10% by weight. The mixture was stirred at 350 rpm for 1 hour, and the temperature was maintained at 65 ° C. Next, 0.25 g of potassium sulfate was added to the mixture to start the polymerization reaction. After 16 hours, the monomer was completely consumed. In the present embodiment, by the amount of butyl acrylate in the solution was controlled from 10 to 30 ml, the glass transition temperature can be adjusted within the polystyrene particles located at 50 ^o C to 0 ^o C range.

Example 3 : Preparation of poly ( styrene - butyl methacrylate) core-shell nanospheres <br/> A styrene monomer solution (99.6 parts by weight) was formulated to have a solid content of 10% by weight. The mixture was stirred at 350 rpm for 1 hour, and the temperature was maintained at 65 ° C. Next, 0.25 g of potassium sulfate was added to the mixture to start the polymerization reaction. After the reaction has been carried out for a certain period of time, a butyl methacrylate monomer solution is added to the system for shell construction to form a shell layer made of a styrene-butyl methacrylate copolymer. In the present embodiment, by the amount of butyl methacrylate monomer solution is controlled at 10-30 ml, the glass transition temperature can be adjusted within the shell located 40 ^o C to 26 ^o C range.

Example 4 : Preparation of poly ( styrene - butyl acrylate) core-shell nanospheres <br/> A styrene monomer solution (99.6 parts by weight) was formulated to have a solid content of 10% by weight. The mixture was stirred at 350 rpm for 1 hour, and the temperature was maintained at 65 ° C. Next, 0.25 g of potassium sulfate was added to the mixture to start the polymerization reaction. After the reaction has been carried out for a certain period of time, a butyl acrylate monomer solution is added to the system for shell construction to form a shell made of a styrene-butyl acrylate copolymer. In the present embodiment, by the amount of butyl acrylate monomer solution is controlled at 10-30 ml, the glass transition temperature can be adjusted within the shell located 10 ^o C to 0 ^o C range.

Example 5 : Preparation of poly ( butyl methacrylate - styrene ) core-shell structure nanospheres <br/> A butyl methacrylate monomer solution (99.6 parts by weight) was formulated to have a solid content of 10% by weight . The mixture was stirred at 350 rpm for 1 hour, and the temperature was maintained at 65 ° C. Next, 0.25 g of potassium sulfate was added to the mixture to start the polymerization reaction. After the reaction has been carried out for a certain period of time, a styrene monomer solution is added to the system for shell construction to form a shell made of a styrene-butyl methacrylate copolymer. In the present embodiment, by controlling the amount of the styrene monomer solution in 10 to 30 ml, the glass transition temperature can be adjusted within the shell located 50 ^o C to 80 ^o C range.

Example 6 : Preparation of poly ( butyl acrylate - styrene ) core-shell structure nanospheres <br/> A butyl acrylate monomer solution (99.6 parts by weight) was formulated to have a solid content of 10% by weight. The mixture was stirred at 350 rpm for 1 hour, and the temperature was maintained at 65 ° C. Next, 0.25 g of potassium sulfate was added to the mixture to start the polymerization reaction. After the reaction has been carried out for a certain period of time, a styrene monomer solution is added to the system for shell construction to form a shell made of a styrene-butyl acrylate copolymer. In the present embodiment, by controlling the amount of the styrene monomer solution in 10 to 30 ml, the glass transition temperature can be adjusted within the shell located 50 ^o C to 80 ^o C range.

Example 7: Preparation of three-dimensional ordered microstructure <br/> prepared 30% aqueous solution of methanol, the boiling point of water at the time of measurement is about 95 ^o C. Prepared in Example 1 nanospheres are suspended in the aqueous methanol solution in which the nanospheres glass transition temperature of 80 ^o C, a particle size of 600 nm. The suspension was placed in a centrifuge tube with an inner diameter of 1.6 cm, and the nanospheres were allowed to self-assemble until the nanospheres filled the centrifuge tube, forming a columnar three-dimensional ordered microstructure with a length of 4 cm and a diameter of 1.6 cm. Place the centrifuge tube in a DENG YNG DO60 hot air loop oven and heat and dry the three-dimensional ordered microstructure for 30 minutes at 77 ^o C (3 ^o C lower than the T _{g of the} nanosphere) to remove the solvent . FIG. 5 shows a three-dimensional ordered microstructure made according to this embodiment, in which the nanospheres arranged in the hexagonal closest packing are slightly deformed and slightly hexagonal, so there is a large area of contact between adjacent nanospheres. Suitable for use as a template to make monolithic columns.

Example 8 : Preparation of a three-dimensional ordered porous microstructure <br/> Hydroxyethyl methacrylate (HEMA) precursor was added to a centrifuge tube, and the three-dimensional ordered microstructure obtained in Example 7 was used as a template. Centrifugation was applied to cause HEMA to fill the pores of the stencil and then cured in a 55 ^o C water bath. After the curing is completed, the structure is taken out, cut to a diameter corresponding to a stainless steel HPLC pipe column, and the structure is tightly bonded to the pipe wall of the HPLC pipe column with an encapsulant. The structure enclosed in the column was subjected to the Soxhlet extraction method, and the solution was continuously extracted with toluene for 5 days. The viscosity of the solvent was maintained at 0.2 to 0.6 psi during the extraction, thereby removing the template to obtain a finished product of the entire column.
FIG. 6 shows that the Soxhlet extraction method in this embodiment can make the solvent easily enter the pores below the micrometer scale, and then dissolve the particles and bring out the microstructure, thereby completely removing the stencil material. The three-dimensional ordered porous microstructure made according to this embodiment is formed with spherical macropores with a diameter of 600 nanometers arranged in the most densely packed form, and communicating pores with a diameter of 250 nanometers that communicate with the macropores. In contrast, as shown in Figure 7, the conventional immersion method cannot completely remove the stencil material.

Example 9 : Preparation of three-dimensional ordered microstructures and three-dimensional ordered porous microstructures <br/> The procedures of Examples 7 and 8 were repeated, but the heating temperature of the three-dimensional ordered microstructures was reduced to 65 ^o C (compared to in nanospheres low T _g of 15 ^o C), for 120 minutes. FIG. 8 shows the manufactured three-dimensional ordered porous microstructure, in which spherical macropores with a diameter of 600 nanometers arranged in the most densely packed form, and communicating pores with a diameter of 150 nanometers that connect the macropores are formed.

Example 10 : Preparation of a three-dimensional ordered microstructure <br/> Repeat the preparation procedure of Example 7, and also use the nanosphere prepared in Example 1, but the particle size is 1 micron, and the three-dimensional ordered microstructure the heating temperature was raised to 100 ^o C (compared to the high T _g of Na Nami ball 20 ^o C), heated for 3 min. Subsequently, the temperature was lowered to 75 ^o C (5 ^o C lower than the T _{g of the} nanosphere), and the three-dimensional ordered microstructure was dried by heating for 30 minutes to remove the solvent. FIG. 9 shows a three-dimensional ordered microstructure made according to this embodiment, in which the nanospheres arranged in the hexagonal closest packing are slightly deformed and slightly hexagonal, so there is a large area of contact between adjacent nanospheres. Suitable for use as a template to make monolithic columns.

Comparative Example 1 : Preparation of a three-dimensional ordered microstructure <br/> The preparation process of Example 7 was repeated, but the heating temperature of the three-dimensional ordered microstructure was reduced to 60 ^o C (20 ^o lower than the T _{g of the} nanosphere ⁾ C). After 30 minutes of drying, most of the solvent has still not been removed. The final drying time was 80 minutes. FIG. 10 shows a three-dimensional ordered microstructure made according to the present comparative example, in which the nanospheres are arranged in the hexagonal close-packed arrangement, and each nanosphere is still substantially spherical, and the contact between them is not obvious.

Comparative Example 2 : Preparation of a three-dimensional ordered microstructure <br/> The preparation process of Example 7 was repeated, but the heating temperature of the three-dimensional ordered microstructure was increased to 90 ^o C (10 _g higher than the T _{g of the} nanosphere) ^o C), drying for 15 minutes. FIG. 11 shows a three-dimensional ordered microstructure made according to this comparative example, in which the nanospheres are arranged in the hexagonal densest packing arrangement, and are approximately regular hexagons, which have been completely in close contact with each other and have no pores. This structure cannot be used as a template.

Comparative Example 3 : Preparation of a three-dimensional ordered microstructure <br/> The preparation process of Example 7 was repeated, but the heating temperature of the three-dimensional ordered microstructure was increased to 110 ^o C (30 _g higher than the T _{g of the} nanosphere) ^o C), drying for 10 minutes. FIG. 12 shows a three-dimensional microstructure made according to this comparative example, in which the nanospheres are melted at a high temperature, the shape is difficult to recognize, and they are completely in close contact with each other without gaps. This structure cannot be used as a template.

Compared with the conventional conventional method, the three-dimensional ordered porous microstructure manufacturing method disclosed in the present invention heat-treats the three-dimensional ordered microstructure at a temperature slightly lower than the glass transition temperature of the particles to remove the solvent used for the suspended particles. , And effectively improve the orderly arrangement of particles between contacts. Compared with a monolithic column made by a conventional method, the monolithic column made according to the manufacturing method has the structural characteristics of high aspect ratio and regularity of high pores, and the communication holes in the column also have relatively large pore diameters.

The above embodiments are only for the purpose of illustrating the present invention, rather than limiting the present invention. Various alterations or changes made by those skilled in the related art without departing from the technical scope of the present invention should also belong to the protection scope of the present invention.

R‧‧‧ longest radius

r‧‧‧ shortest radius

FIG. 1 is a flowchart according to an embodiment of the present invention;

2 is an electron microscope photograph of polystyrene particles softened without heating;

FIG. 3 is an electron micrograph of polystyrene particles softened by heating, which shows that the particles begin to deform;

4 is an electron microscope photograph of polystyrene particles deformed by heat for a long time;

5 is an electron microscope photograph of a three-dimensional ordered microstructure made according to an embodiment of the present invention;

FIG. 6 shows a cross-sectional electrical display photograph of a three-dimensional ordered porous microstructure made by removing a three-dimensional ordered microstructure using Soxhlet extraction according to an embodiment of the present invention;

7 shows an electron microscope photograph of a three-dimensional ordered porous microstructure made by removing a three-dimensional ordered microstructure by a conventional immersion method;

FIG. 8 shows a cross-sectional electrical display photograph of a three-dimensional ordered porous microstructure made according to another embodiment of the present invention; FIG.

FIG. 9 is a sectional electric display photograph of a three-dimensional ordered microstructure made in another embodiment of the present invention; FIG.

10 is a cross-sectional electrical display photograph of a three-dimensional ordered microstructure made according to a comparative example;

11 is a cross-sectional electrical display photograph of a three-dimensional ordered microstructure made according to another comparative example; and

FIG. 12 is a sectional electric display photograph of a three-dimensional ordered microstructure made according to another comparative example.

Claims (2)

A method for manufacturing a three-dimensional ordered porous microstructure, comprising the following steps: A. forming a three-dimensional ordered microstructure composed of a plurality of substantially spherical particles, so that there are multiple voids between the plurality of particles; B Deforming substantially spherical particles in the three-dimensional ordered microstructure, so that the particles are deformed to have a longest radius R and a shortest radius r, where the ratio r / R is greater than / 2 but less than 1; C. filling an anti-structure material into the void; and D. removing the three-dimensional ordered microstructure to obtain the three-dimensional ordered porous microstructure. A monolithic column manufactured by the method for manufacturing a three-dimensional ordered porous microstructure according to claim 1.