Preparation method and application of soft-hard colloid particle macroscopic composite material

Abstract

The invention discloses a preparation method and application of a soft-hard colloid particle macroscopic composite material, and the preparation method comprises the following steps: (1) uniformly mixing PS-b-P2VP block copolymer micelles and SiO2 nanoparticles in an organic solvent, and carrying out aging and stirring treatment to obtain a solution assembly; (2) carrying out centrifugal treatment on the solution assembly, collecting solids, and drying to obtain a secondary assembly; and (3) placing the secondary assembly in a mold, and carrying out hot press molding and drying to obtain the soft-hard colloid particle macroscopic composite material. According to the preparation method, scale spanning from a nanoscale assembly element to a macroscopic self-assembly composite material is realized, and the formed soft-hard colloid particle macroscopic composite material has good mechanical stability, dynamic deformability, multi-element loading and cyclic regeneration capability; the transparent glass with a customized shape can be prepared through further pyrolysis and sintering, and a new thought is provided for cross-scale manufacturing and processing of nano functional materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nanofunctional materials, in particular to a preparation method and application of soft-hard colloidal particle macroscopic composite material. BACKGROUND

[0002] Since Mirkin et al. and Alivisatos et al. used DNA to induce the self-assembly of Au nanoparticle solution to form colloidal superlattice and colloidal molecules in 1996, colloidal particle self-assembly has been considered as one of the ideal means for constructing multi-level and multi-functional materials from bottom to top, and scientists have high hopes for customizing composition and structure. Therefore, in the past 30 years, as one of the potential means for creating revolutionary materials and devices, the colloidal self-assembly technology has attracted widespread attention from the scientific community and has experienced a flourishing development. So far, the controllable assembly of colloidal particles can be realized by external templates, surface ligands, anisotropy, and external light, electricity, and magnetic field induction, and a series of attractive colloidal structures have been prepared, including low-dimensional clusters and chains, and high-dimensional thin films, single crystals, and polycrystalline superlattices. However, with the continuous development and progress of science and technology, the pursuit of new materials and new devices has prompted scientists to no longer limit the development of colloidal assembly structure control methodology only on the microscale, but to start exploring the creation of multifunctional and practical colloidal self-assembly composite materials on the macroscale. For example, Liu et al. used gold nanorods and human islet amyloid polypeptide (hIAPP) to cooperatively assemble to prepare long-range ordered nanohelix fibers, which were used for amyloid-like drug screening. Xu et al. used chiral phenylalanine-modified gold nanoparticles to self-assemble into chiral nanomembranes at the liquid-liquid interface, which were used for precise detection of circularly polarized light.

[0003] Although scientists have made great progress in the application field of colloidal assembly, it is still challenging to realize the scale span from nanobuilding blocks to macroscopic self-assembly composite materials. On the one hand, colloidal self-assembly often requires pre-modification of assembly building blocks, and sometimes the assembly process needs several days to obtain long-range ordered superlattice structures; on the other hand, the destructive cracks that occur in the preparation and processing of macroscopic colloidal composite materials will affect the further application of the materials. Therefore, it is of great significance to construct macroscopic colloidal composite materials with mechanical stability using simple colloidal particles. SUMMARY

[0004] To solve the problems of long time, poor workability and poor performance in the preparation of macroscopic self-assembled composite materials from nano building blocks, which limits the practical production and application of such macroscopic self-assembled composite materials. The present application provides a preparation method and application of soft-hard colloidal particle macroscopic composite material, using PS-b-P2VP block copolymer micelles and SiO2 nanoparticles as soft and hard colloidal particles. By simply mixing soft and hard colloidal particles, centrifugal induced secondary assembly and mold assisted hot pressing forming, macroscopic colloidal composite material is successfully prepared. The preparation method is simple, and the soft-hard colloidal particle macroscopic composite material formed has good mechanical stability, dynamic deformation, multi-element loading and cyclic regeneration capacity. It can be further pyrolyzed and sintered to prepare transparent glass with customized shape, providing a new idea for the cross-scale manufacturing and processing of nano functional materials.

[0005] Specifically, the following technical solutions are provided:

[0006] The first aspect of the present application provides a preparation method of soft-hard colloidal particle macroscopic composite material, comprising the following steps:

[0007] (1) uniformly mix PS-b-P2VP block copolymer micelles and SiO2 nanoparticles in an organic solvent, and after aging and stirring treatment, obtain a solution assembly of soft-hard colloidal particles;

[0008] (2) centrifuge the solution assembly of soft-hard colloidal particles, collect the solid and dry to obtain a secondary assembly of soft-hard colloidal particles;

[0009] (3) place the secondary assembly of soft-hard colloidal particles in a mold, and after hot pressing forming and drying, obtain the soft-hard colloidal particle macroscopic composite material.

[0010] Further, in step (1), the polymerization degree of monomer styrene in the PS-b-P2VP block copolymer is 400-2200, and the polymerization degree of monomer 2-vinylpyridine is 100-2600. The higher the polymerization degree of P2VP in the PS-b-P2VP block copolymer, the longer the length of the crown of the PS-b-P2VP block copolymer micelle particle formed, and the number of micelles adsorbed on the surface of the SiO2 nanoparticles gradually decreases, thereby reducing the saturation valence of the SiO2 nanoparticles, resulting in the inability to achieve a stable form, thereby affecting the mechanical properties of the macroscopic composite material. However, the polymerization degree of P2VP cannot be too low, otherwise the crown of the PS-b-P2VP block copolymer micelle particle formed is too short, and cannot form an effective contact surface with the SiO2 nanoparticles, thereby affecting the mechanical properties of the macroscopic composite material. Preferably, the polymerization degree of monomer styrene in the PS-b-P2VP block copolymer is controlled within the range of 400-2200, and the polymerization degree of monomer 2-vinylpyridine is controlled within the range of 100-2600.

[0011] Further, in step (1), the particle size of the PS-b-P2VP block copolymer micelle is 40-70 nm, for example 54 nm, and the particle size of the SiO2 nanoparticles is 50-340 nm, for example 91 nm.

[0012] Further, in step (1), the number ratio of the PS-b-P2VP block copolymer micelle to the SiO2 nanoparticles is 1:2-4:1, for example 1:2, 1:1, 2:1, 3:1, 4:1, etc., and more preferably 4:1.

[0013] In the present application, the number ratio of the PS-b-P2VP block copolymer micelles and the SiO2 nanoparticles will affect the secondary assembly effect and the mechanical properties of the formed macroscopic composite material. If the number ratio of the PS-b-P2VP block copolymer micelles and the SiO2 nanoparticles is less than 1:2, a colloidal oligomer capped by SiO2 nanoparticles will be formed. After centrifugal treatment, the oligomers will be randomly stacked to form secondary assemblies. Due to the excessive number of SiO2 nanoparticles, the oligomers are mainly stacked by the SiO2 particles of each other, resulting in that the formed soft-hard colloidal particle macroscopic composite material is mainly combined together by the van der Waals force between the SiO2 particles of adjacent oligomers, and the mechanical properties are poor. With the increase of the number ratio of the PS-b-P2VP block copolymer micelles and the SiO2 nanoparticles, the “hard-hard” contact in the formed macroscopic composite material is reduced, and a solution assembly with a macroscopic network structure formed by alternatingly bonding soft and hard particles is gradually formed. The solution assembly with a macroscopic network structure has an unused P2VP micellar crown and an uncovered SiO2 particle surface. After centrifugal induced stacking, the solution assemblies are secondarily assembled by means of these active sites to form a macroscopic composite material with larger size and excellent mechanical properties. However, if the number ratio of the PS-b-P2VP block copolymer micelles and the SiO2 nanoparticles is too large, for example, greater than 4:1, the SiO2 nanoparticles in the formed solution assembly will be completely covered by the P2VP crown of the soft micelle particles, and there is a lack of active sites. After centrifugal induced stacking, the solution assemblies cannot form tightly combined secondary assemblies, thereby affecting the uniformity of the soft-hard colloidal particle macroscopic composite material prepared by subsequent hot pressing, and further affecting the mechanical properties of the macroscopic composite material. Therefore, in order to obtain a macroscopic composite material with large size, good uniformity and excellent mechanical properties, preferably, the number ratio of the PS-b-P2VP block copolymer micelles and the SiO2 nanoparticles is controlled in the range of 1:2-4:1.

[0014] Further, in step (1), the PS-b-P2VP block copolymer micelles are prepared by the following method:

[0015] S1, under an inert atmosphere, a certain molar ratio of monomers styrene and 2-vinylpyridine are subjected to a polymerization reaction in the presence of an initiator and a solvent to obtain a PS-b-P2VP block copolymer; preferably, the initiator is s-BuLi, and the solvent is THF;

[0016] S2, the PS-b-P2VP block copolymer is dissolved in a solvent, methanol is added while stirring, and then the obtained solution is subjected to dialysis in ethanol, and impurities are removed by filtration to obtain the PS-b-P2VP block copolymer micelles; the solvent is THF.

[0017] Further, in step (1), the SiO2 nanoparticles are prepared by the following method:

[0018] S1, dissolving L-arginine in water, then adding TEOS, heating and stirring to obtain a SiO2 nanoparticle seed solution; preferably, the temperature of heating and stirring is 70℃, and the time is 24h;

[0019] S2, dissolving L-arginine in water, then adding the SiO2 nanoparticle seed solution and TEOS, stirring and aging to obtain the SiO2 nanoparticles; the SiO2 nanoparticles are washed by centrifugation with distilled water for multiple times and dispersed in ethanol for use; preferably, the temperature of stirring and aging is 20-40℃, and the time is 12h.

[0020] Further, in step (1), the organic solvent includes but is not limited to ethanol.

[0021] Further, in step (1), the temperature of aging is 80-100℃, and the time of aging is 2-3h.

[0022] Further, in step (1), the temperature of stirring treatment is 20-40℃, and the time of stirring treatment is 10-12h.

[0023] Further, in step (2), the centrifugation treatment is specifically: collecting the solution assembly of soft-hard colloidal particles in a centrifuge tube, and centrifuging at 8000-12000g for 20-40min. If the centrifugal force is too small, it will lead to ineffective separation, uneven separation, etc., and if the centrifugal force is too large, it will lead to changes in the structure of soft and hard particles, and it is impossible to form a uniform and stable macroscopic colloidal composite material, therefore, preferably, the centrifugal force is controlled within the range of 8000-12000g.

[0024] Further, in step (2), the drying temperature is 60-80℃, and the time is 18-24h.

[0025] Further, in step (3), in the hot pressing forming step: the pressure is 0.01-0.04t, the pressure holding time is 1-2h, and the temperature is 40-60℃.

[0026] Further, in step (3), the drying temperature is 60-80℃, and the time is 18-24h.

[0027] Further, by pre-designing the shape of the mold cavity, a macroscopic colloidal composite material with a target shape is prepared.

[0028] The second aspect of the application provides a soft-hard colloidal particle macroscopic composite material prepared by the preparation method of the first aspect.

[0029] The third aspect of the present application provides an application of the soft-hard colloidal particle macro-composite material of the second aspect in preparing transparent quartz glass.

[0030] The traditional glass processing method usually needs to burn the glass to above 1000℃, and then shape and process the glass at high temperature, which has problems such as high energy consumption, complex process, and difficulty in doping functional nanoparticles (such as fluorescent particles); and the fluorescent glass usually introduces luminescent centers by melt quenching or ion exchange, which faces problems such as low luminescent efficiency and significant reduction in transparency caused by particle agglomeration. The present application uses the above-mentioned soft-hard colloidal particle macro-composite material to prepare transparent quartz glass, and the soft colloidal particles used to connect the hard particles have dynamic deformation ability, so only need to pre-shape the sample at a relatively low temperature (100℃, for example 40-60℃), and then pyrolysis and sintering, so as to obtain a transparent quartz glass product with a target shape. Specifically, since the soft-hard colloidal particle macro-composite material connects the SiO2 nanoparticles into a whole in an alternating manner of soft and hard particles, the soft-hard colloidal particle macro-composite material with a preset shape is pyrolyzed in air to remove the polymer micelle component, and the SiO2 nanoparticle skeleton with a preset shape can be reserved. Further vacuum sintering can induce the adjacent SiO2 particles in the SiO2 nanoparticle skeleton to gradually fuse with each other to form "worm-like" SiO2 oligomers, and then melt to form a cross-linked SiO2 network. With the continuous deepening of the polymerization degree, the densification degree of the material is continuously increased, and further evolves into a porous SiO2 block, and finally forms a continuous and dense fused quartz glass block. And based on the uniform distribution of SiO2 nanoparticles in the soft-hard colloidal particle macro-composite material, the prepared quartz glass still retains the preset shape (isometrically reduced in all directions). The preparation method is simple and has low energy consumption, and can prepare quartz glass with customized shape, and the prepared quartz glass is dense, defect-free, crack-free and has high light transmittance. In addition, only need to immerse the above-mentioned soft-hard colloidal particle macro-composite material in a solution containing rare earth ions before pyrolysis, and use the large number of pyridine groups in the P2VP crown layer of the PS-b-P2VP block copolymer micelles to combine with the rare earth ions, and after pyrolysis and sintering treatment, a fluorescent transparent quartz glass is prepared. The preparation method is simple, and the fluorescent glass prepared by this method still has high transparency.

[0031] Further, the soft-hard colloidal particle macro-composite material is pyrolyzed and sintered to obtain the transparent quartz glass; preferably, the pyrolysis is performed in air, the temperature of the pyrolysis is 1000-1100℃, the heating rate is 3℃ / min, and the pyrolysis time is 4-6h; the sintering is performed under vacuum, the temperature of the sintering is 1100-1200℃, the heating rate is 3℃ / min, and the sintering time is 2-3h.

[0032] Further, the transparent quartz has a transmittance of greater than 80% in the wavelength range of 400nm-1000nm, and a transmittance of greater than 70% at 200nm.

[0033] Further, when the transparent quartz glass is a fluorescent transparent quartz glass, the soft-hard colloidal particle macro-composite material is first immersed in an alcohol solution containing rare earth ions, and then taken out for pyrolysis and sintering.

[0034] Further, when the rare earth ions are Eu 3+ , the fluorescent transparent quartz glass emits red fluorescence under 254nm ultraviolet light; when the rare earth ions are Ce 3+ , the fluorescent transparent quartz glass emits blue fluorescence under 254nm ultraviolet light.

[0035] The present application has the following advantages:

[0036] 1. The present application provides a preparation method of a soft-hard colloidal particle macro-composite material, which uses PS-b-P2VP block copolymer micelles and SiO2 nanoparticles as soft and hard colloidal particles, and successfully prepares a macro-scale colloidal composite material through simple mixing of the soft and hard colloidal particles, centrifugal-induced secondary assembly, and mold-assisted hot-pressing molding; the above preparation method is simple in operation and strong in processability, realizes the scale leap from nanometer building blocks to macroscopic self-assembled composite materials, and the soft-hard colloidal particle macro-composite material prepared by the above method has good mechanical stability, dynamic deformation, multi-element loading, and recycling ability (the copolymer micelles have solvent-responsive reversibility, so that the soft-hard colloidal particle macro-composite material constructed therefrom has recycling ability), thereby providing a new idea for the cross-scale manufacturing and processing of nanometer functional materials.

[0037] 2, The soft-hard colloidal particle macroscopic composite material prepared by the application can be used for preparing transparent quartz glass, compared with traditional glass processing which needs high temperature (above 1000 DEG C) shaping and processing, the application only needs to pre-shape the sample at a relatively low temperature (100 DEG C), then pyrolysis and sintering are carried out, so that the transparent glass product with the target shape can be obtained, the preparation method is simple, the energy consumption is low, and the glass product with more complex and more arbitrary shape can be prepared.

[0038] 3, The soft-hard colloidal particle macroscopic composite material prepared by the application can realize further functional modification of the composite material by utilizing the fact that a large number of pyridine groups are rich in the P2VP crown layer in the soft colloidal particle, so as to prepare functionalized quartz glass, for example, fluorescent transparent quartz glass. The fluorescent transparent quartz glass prepared by the soft-hard colloidal particle macroscopic composite material through simple dipping, pyrolysis and sintering has not only good and stable fluorescent performance, but also good transparency. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 It is a flowchart of preparing macroscopic composite material by nano building blocks of the application;

[0040] Figure 2 It is the SEM image of the solution assembly (left figure) and the secondary assembly (right figure) prepared in example 1;

[0041] Figure 3 It is the SEM image of the solution assembly (left figure) and the secondary assembly (right figure) prepared in example 2;

[0042] Figure 4 It is the SEM image of the solution assembly (left figure) and the secondary assembly (right figure) prepared in example 3;

[0043] Figure 5 It is the SEM image of the solution assembly (left figure) and the secondary assembly (right figure) prepared in example 4;

[0044] Figure 6 It is the photo of the soft-hard colloidal particle macroscopic composite material of part of the cylinder and the cuboid prepared in examples 1-4;

[0045] Figure 7 It is the uniaxial compression test of the cylinder sample: a is the stress-strain curve of the uniaxial compression test, and b is the compression strength of the sample;

[0046] Figure 8 It is the three-point bending test of the cuboid sample: a is the stress-strain curve of the three-point bending test, and b is the bending strength of the sample;

[0047] Figure 9Creep and recovery test of soft-hard colloidal particle macro-composites prepared in Example 3: a is the creep and recovery curve of the sample under different loads at 25℃, b is the creep and recovery curve of the sample under 2.50 MPa load at different temperatures;

[0048] Figure 10 : a is the comparison of the creep and recovery curves of different soft-hard colloidal particle macro-composites, b is the comparison of the creep strain and residual strain;

[0049] Figure 11 : a is the schematic diagram of the preparation process of soft-hard colloidal particle macro-composites for preparing transparent quartz glass, b is the SEM image of the material at different stages;

[0050] Figure 12 : a is the UV-visible transmission spectrum of the transparent quartz glass, b is the SEM image of the cross section of the transparent quartz glass;

[0051] Figure 13 Schematic diagram of the preparation process of fluorescent transparent glass prepared by different soft-hard colloidal particle macro-composites;

[0052] Figure 14 Photo of fluorescent transparent glass under sunlight;

[0053] Figure 15 Photo of fluorescent transparent glass under 254 nm ultraviolet light irradiation;

[0054] Figure 16 Flow chart of preparing macro-sized fused quartz glass by cross-scale co-assembly of nano-sized soft and hard colloidal particles. DETAILED DESCRIPTION

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. The use of the terms "include", "includes", "including", "comprising", "comprises", "comprising", or "comprises" is not limiting of the application to the specific techniques so far described, and one of ordinary skill in the art will recognize further methods upon consideration of this disclosure.

[0056] The application will be further described with reference to the drawings and specific examples, so that those skilled in the art can better understand the application and implement it.

[0057] Example 1

[0058] This example relates to the preparation of a soft-hard colloidal particle macro-composite, the specific operation is as follows:

[0059] (1) Preparation of PS2060-b-P2VP300 block copolymer micelles:

[0060] In a glove box, a dry Schlenk flask was charged with 20 mL THF, 71.4 μL s-BuLi solution (0.1 mmol) was added by syringe and stirred for 5 min under argon protection. 21.45 g of styrene was injected into the reaction flask and the solution immediately turned orange red (active chain signature). The reaction was allowed to proceed for 1 h at -78 °C, then slowly warmed to 25 °C and continued for 2 h until the red color disappeared (indicating monomer exhaustion). 3.15 g of 2-vinylpyridine was injected into the reaction flask and the solution turned deep red. The reaction was allowed to proceed for 4 h at 25 °C. 1 mL of methanol was added to quench the active chains and the red color disappeared. The reaction solution was then poured into 200 mL of cold methanol to precipitate and a white solid was obtained by filtration. The solid was redissolved in THF, purified by dialysis (MWCO 3500) and freeze-dried to give PS2060-b-P2VP300 block copolymer.

[0061] A 2 g of PS2060-b-P2VP300 diblock copolymer solid was thoroughly dissolved in 200 mL of anhydrous THF. Then, 800 mL of methanol was slowly added at a rate of 40 mL / h under stirring at room temperature. Finally, the resulting solution was dialyzed against ethanol to remove THF and then filtered through a polytetrafluoroethylene filter membrane with a pore size of 0.22 μm to remove impurities to obtain an ethanol solution of PS2060-b-P2VP300 block copolymer micelles.

[0062] Preparation of SiO2 nanoparticles:

[0063] A 17.4 mg of L-arginine and 17.4 mL of distilled water were thoroughly stirred and dissolved for 10 min, then 1.12 mL of TEOS was added, and the solution was heated to 70 °C and vigorously stirred for 24 h. After naturally cooling to room temperature, a SiO2 nanoparticle seed solution was obtained.

[0064] A 6.572 g of L-arginine, 3 L of ethanol, 924 mL of distilled water were thoroughly stirred and dissolved for 10 min, and the solution was heated to 70 °C. Then, 13 mL of the above seed solution was added, and 110 mL of TEOS was added at a rate of 10 mL / h. After the addition of TEOS was completed, the resulting solution was further gently stirred for 12 h for aging. Finally, multiple centrifugal washings with distilled water were performed, and finally dispersed in ethanol to obtain an ethanol solution of SiO2 nanoparticles.

[0065] (2) At 80°C, under vigorous stirring, add the ethanol solution of SiO2 nanoparticles with a size of 91 nm into the ethanol solution of PS2060-b-P2VP300 block copolymer micelles (the number ratio of PS2060-b-P2VP300 block copolymer micelles to SiO2 nanoparticles S:H = 1:2), and age at this temperature for 2 h. After the obtained solution is naturally cooled to room temperature, continue to stir the solution gently for 12 h to obtain the solution assembly of soft-hard colloidal particles, the SEM image of which is shown in the left image of Figure 2 Figure 1.

[0066] (3) Collect the solution assembly of soft-hard colloidal particles in a centrifuge tube, centrifuge at 12000 g at room temperature for 30 min. Then, dry the obtained solid at 60°C for 24 h to obtain the secondary assembly of soft-hard colloidal particles, the SEM image of which is shown in the right image of Figure 2 Figure 1. During the centrifugation, the solution assemblies are forced to continuously accumulate at the bottom of the centrifuge tube by the action of centrifugal force, and secondary combination occurs to form the secondary assembly.

[0067] (4) Place the secondary assembly of soft-hard colloidal particles obtained after centrifugation in a pre-customized stainless steel mold cavity, apply a pressure of about 0.02 t to the mold at 40°C, and maintain the pressure for 2 h to shape the sample. Then, take out the shaped sample from the mold, and continue to dry at 60°C for 24 h to obtain the soft-hard colloidal particle macro-composite material; by changing the shape of the mold, cylindrical and cuboid soft-hard colloidal particle macro-composite materials are prepared, respectively.

[0068] Example 2

[0069] This example relates to the preparation of a soft-hard colloidal particle macro-composite material, which is only different from Example 1 in that in step (2), the number ratio of PS2060-b-P2VP300 block copolymer micelles to SiO2 nanoparticles S:H = 1:1, and the rest of the operations are consistent, and the corresponding cylindrical and cuboid soft-hard colloidal particle macro-composite materials are prepared.

[0070] The SEM image of the solution assembly of soft-hard colloidal particles prepared in this example is shown in the left image of Figure 3 Figure 2, and the SEM image of the secondary assembly of soft-hard colloidal particles is shown in the right image of Figure 3 Figure 2. As can be seen from the images, the secondary combination of the solution assemblies occurs to form the secondary assembly under the action of centrifugal force.

[0071] Example 3

[0072] The embodiment relates to preparation of a soft-hard colloidal particle macro-composite material, and the difference from the embodiment 1 is that the number ratio S:H of the PS2060-b-P2VP300 block copolymer micellar particles and SiO2 nanoparticles in step (2) is 2:1, and the rest operations are consistent, so that the corresponding cylindrical and cuboid soft-hard colloidal particle macro-composite materials are prepared.

[0073] The SEM image of the solution assembly of the soft-hard colloidal particles prepared in the embodiment is shown in the left part of FIG. 7, and the SEM image of the secondary assembly of the soft-hard colloidal particles is shown in the right part of FIG. 7. Figure 4 Figure 4 It can be known from the figures that the solution assembly is combined to form the secondary assembly under the action of the centrifugal force.

[0074] Embodiment 4

[0075] The embodiment relates to preparation of a soft-hard colloidal particle macro-composite material, and the difference from the embodiment 1 is that the number ratio S:H of the PS2060-b-P2VP300 block copolymer micellar particles and SiO2 nanoparticles in step (2) is 4:1, and the rest operations are consistent, so that the corresponding cylindrical and cuboid soft-hard colloidal particle macro-composite materials are prepared.

[0076] The SEM image of the solution assembly of the soft-hard colloidal particles prepared in the embodiment is shown in the left part of FIG. 7, and the SEM image of the secondary assembly of the soft-hard colloidal particles is shown in the right part of FIG. 7. Figure 5 Figure 5 It can be known from the figures that the solution assembly is combined to form the secondary assembly under the action of the centrifugal force.

[0077] Test example

[0078] The soft-hard colloidal particle macro-composite materials prepared in the above embodiments 1-4 are subjected to mechanical property tests, and the details are as follows.

[0079] (1) The uniaxial compression test is carried out on the cylindrical sample, and the stress-strain curves and compression strengths of different soft-hard colloidal particle macro-composite materials are respectively shown in FIGS. 7a and 7b. Figure 7 It can be known from the figures that the compression strength of the macro-composite material is continuously improved along with the increase of the soft micellar particle content, because the micelles consume the external energy by deformation and tearing in the compression process of the material, so as to play a certain toughening role and improve the strength of the material.

[0080] (2) The three-point bending test is carried out on the cuboid sample, and the stress-strain curves and bending strengths of different soft-hard colloidal particle macro-composite materials are respectively shown in FIGS. 8a and 8b. Figure 8 ​​a, 8b, it can be seen from the figure that the bending strength of the macroscopic composite material increases with the increase of the content of soft micellar particles. This is because the polymer soft micellar particles play a bonding role in the material. The more tightly the soft and hard building blocks of the colloidal composite material combine with each other, the stronger the bending strength of the material.

[0081] (3) Based on the three-point bending test mode, further study the creep and recovery behavior of soft-hard colloidal particle macroscopic composite material under different loads and temperatures.

[0082] Figure 9 a is the creep and recovery curve of the soft-hard colloidal particle macroscopic composite material prepared in Example 3 at 25℃ under different loads. As can be seen from the figure, at room temperature, the sample is subjected to an external force of 1.25MPa, 2.50MPa and 3.75MPa respectively. The strain increases almost instantaneously and balances to a certain value, and during the process of time extension to 1500s, the strain almost does not change any more. Moreover, with the increase of the applied load, the creep value of the material also increases, because the creep of the colloidal composite material comes from the deformation of PS-b-P2VP micelles. At room temperature, PS is in a glassy state, resulting in the "frozen" state of the micellar core composed of PS molecular chains, which has the characteristics of Hookean elastic body with small deformation and instantaneous stress-strain response. Then, the strain decreases instantaneously and balances to a certain value, and during the process of time extension to 2300s, the strain almost does not change any more. Moreover, with the increase of the applied load, the residual strain value of the material after creep recovery also increases, which may be due to the permanent deformation of PS-b-P2VP micelles under the action of external force for a long time, resulting in the deformation of the colloidal composite material cannot be completely recovered.

[0083] Figure 9 b is the creep and recovery curve of the soft-hard colloidal particle macroscopic composite material under the load of 2.50MPa at different temperatures. As can be seen from the figure, with the increase of the environmental temperature, the creep behavior of the material becomes more and more obvious. When at room temperature, the stress and strain of the material are almost instantaneous response. When the environmental temperature rises, the strain of the material increases slowly with time after the initial jump, and the increasing trend is enhanced with the increase of temperature. In addition, the residual strain of the colloidal composite material after creep recovery also increases with the increase of temperature.

[0084] In addition, the creep and recovery behavior of the soft-hard colloidal particle macroscopic composite material prepared in Example 4 is further tested and compared with the soft-hard colloidal particle macroscopic composite material prepared in Example 3, and the results are shown in Figure 10The results show that the creep behavior is more significant when the micelle content reaches S:H=4:1. Compared with the soft-hard colloidal particle macro-composite prepared in Example 3, which exhibits a 0.7% creep strain and a 0.4% residual strain at 2.50 MPa and 100°C, the soft-hard colloidal particle macro-composite prepared in Example 4 exhibits a greater 5.2% creep strain and a 3.7% residual strain. This time- and temperature-dependent dynamic deformation behavior can be attributed to the relaxation characteristics of the soft polymer micelles. When the ambient temperature is higher than the glass transition temperature, the mobility of the polymer segments is greatly enhanced, resulting in an enhanced deformation ability of the micelles, which in turn endows the colloidal composite with a stronger dynamic deformation ability.

[0085] Application Example 1

[0086] Taking the cylindrical soft-hard colloidal particle macro-composite prepared in Example 4 as an example, a transparent quartz glass is prepared, and a preparation process diagram is shown in Figure 11 a, and the specific operation is as follows:

[0087] The soft-hard colloidal particle macro-composite is pyrolyzed at 1000°C in air for 6 h (the heating rate is 3°C / min), and then vacuum sintered at 1100°C for 6 h (the heating rate is 3°C / min), to prepare a transparent quartz glass.

[0088] Figure 11 b is the SEM diagram of the soft-hard colloidal particle macro-composite at different stages in the preparation process, which shows the process of the SiO2 particle accumulation skeleton gradually densifying through fusion to form a fused quartz glass. As can be seen from the figure, during the sintering process, "polymerization" can occur between the monomer SiO2 nanoparticles, first forming "worm"-like SiO2 oligomers (intermediate I), and then fusing to form a cross-linked SiO2 network (intermediate II). As the degree of polymerization continues to deepen, the degree of densification of the material continues to increase, further evolving into a porous SiO2 block (intermediate III), and finally forming a continuous and dense fused quartz glass block.

[0089] The transmittance of the prepared fused quartz glass block is tested, and the results are shown in Figure 12 a. The transmittance in the range of 400 nm-1000 nm is more than 80%, and the transmittance at 200 nm is greater than 70%. In addition, the cross section of the glass is observed by SEM, and as shown in Figure 12 b, the cross section is dense and smooth, and no defects or cracks are observed, proving the effectiveness of the glass preparation method.

[0090] Application Example 2

[0091] Take the cuboid soft-hard colloidal particle macro-composite material prepared in Example 4 as an example, which is used to prepare fluorescent transparent quartz glass, the preparation process is shown in Figure 13 as follows:

[0092] The soft-hard colloidal particle macro-composite material cuboid sample is soaked in a methanol solution containing metal precursors (Eu(NO3)3 or Ce(NO3)3) for 5 min, and then taken out to be pyrolyzed at 1000℃ in air for 6 h (the heating rate is 3℃ / min), and vacuum sintered at 1100℃ for 6 h (the heating rate is 3℃ / min), to prepare a fluorescent transparent quartz glass, as shown in Figure 14 .

[0093] As can be seen from Figure 15 , after the colloidal composite material is doped with Eu(NO3)3 and then pyrolyzed and sintered, a red fluorescent transparent glass under 254 nm ultraviolet light can be finally obtained; and after the colloidal composite material is doped with Ce(NO3)3, a blue fluorescent transparent glass under 254 nm ultraviolet light can be obtained. It can be seen that the doped glass obtained by introducing rare earth ions can emit fluorescence under ultraviolet light, and the fluorescence color can be adjusted by the type of rare earth ions.

[0094] The above examples are only preferred examples for fully illustrating the present application, and the protection scope of the present application is not limited thereto. Any equivalent replacement or transformation of the present application made by the person skilled in the art on the basis of the present application is within the protection scope of the present application. The protection scope of the present application is subject to the claims.

Claims

1. A method for preparing a macroscopic composite material of soft and hard colloidal particles, characterized in that: The following steps are involved: (1) PS-b-P2VP block copolymer micelles and SiO2 nanoparticles are uniformly mixed in an organic solvent, and after aging and stirring, a solution assembly of soft-hard colloidal particles is obtained; (2) centrifuging the solution assembly of the soft-hard colloid particles, collecting and drying the solid to obtain a secondary assembly of the soft-hard colloid particles; (3) placing the secondary assembly of the soft-hard colloid particles in a mold, hot pressing and drying to obtain the soft-hard colloid particle macro composite material.

2. The preparation method according to claim 1, characterized in that In step (1), at least one of the following characteristics must be met: (1) The degree of polymerization of the monomer styrene in the PS-b-P2VP block copolymer is 400-2200, and the degree of polymerization of the monomer 2-vinylpyridine is 100-2600; (2) The particle size of the PS-b-P2VP block copolymer micelles is 40-70 nm, and the particle size of the SiO2 nanoparticles is 50-340 nm; (3) the ratio of the number of PS-b-P2VP block copolymer micelles to SiO2 nanoparticles is 1:2-4:1; (4) The organic solvent is ethanol.

3. The preparation method according to claim 1, characterized in that In step (1), the aging temperature is 80-100° C. and the aging time is 2-3 h; The stirring temperature is 20-40° C., and the stirring time is 10-12 hours.

4. The preparation method according to claim 1, characterized in that In step (2), the centrifugation treatment is specifically as follows: collecting the solution assembly of the soft-hard colloidal particles in a centrifuge tube and centrifuging at 8000-12000 g for 20-40 min; The drying temperature is 60-80°C.

5. The preparation method according to claim 1, characterized in that In step (3), in the hot pressing step: the pressure is 0.01-0.04t, the holding time is 1-2h, and the temperature is 40-60°C; The drying temperature is 60-80°C.

6. A macroscopic composite material of soft-hard colloidal particles prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the soft-hard colloidal particle macro-composite material according to claim 6 in preparing transparent quartz glass.

8. The use according to claim 7, characterized in that pyrolyzing and sintering the soft-hard colloidal particle macro composite material to obtain the transparent quartz glass; The pyrolysis treatment is carried out in air at a temperature of 1000-1100°C; The sintering process is carried out under vacuum conditions at a temperature of 1100-1200°C; The light transmittance of the transparent quartz glass in the wavelength range of 400nm-1000nm is greater than 80%, and the light transmittance at 200nm is greater than 70%.

9. The use according to claim 8, characterized in that When the transparent quartz glass is fluorescent transparent quartz glass, the soft-hard colloidal particle macroscopic composite material is first immersed in an alcohol solution containing rare earth ions, and then taken out for pyrolysis and sintering treatment.

10. The use according to claim 9, characterized in that When the rare earth ion is Eu 3+ When the fluorescent transparent quartz glass emits red fluorescence under 254nm ultraviolet light; When the rare earth ion is Ce 3+ When the fluorescent transparent quartz glass emits blue fluorescence under 254nm ultraviolet light.

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