A method for preparing a randomly dispersed microsphere template on a solid substrate surface and its application

Abstract

The present invention provides a method and application for preparing a disorderly dispersed microsphere template on the surface of a solid substrate, the method comprising: uniformly mixing large-sized microspheres and small-sized microspheres of different sizes; constructing a single-layer microsphere film on the surface of a solid substrate by self-assembly technology; removing the small-sized microspheres by etching technology, thereby obtaining a uniformly dispersed and disorderly arranged large-sized microsphere template on the surface of a solid substrate; the density of the template can be regulated by changing the mixing ratio of large-sized and small-sized microspheres. The technical problem of constructing a density-controllable and disorderly dispersed microsphere template on the surface of a solid substrate is solved. And because the method of the present invention is based on self-assembly technology, it is possible to prepare a microsphere template on the surface of a solid substrate at low cost, large area, and high efficiency, the process is simple and low cost, and is suitable for batch and industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of functional materials, and in particular to a method for preparing a disorderly dispersed microsphere template on the surface of a solid substrate and an application thereof. Background Art

[0002] Constructing microstructures on the surface of solid substrates can give materials special functional properties, thus having broad application prospects in the fields of biomedical materials, chemical sensing, surface-enhanced Raman scattering, super-hydrophobic / super-hydrophobic surfaces, catalysis, etc. For example, in the field of biomedical materials, different micro- or nanostructures on the surface of materials can activate intracellular mechanical signal transduction pathways and initiate intracellular signal cascade reactions, thereby changing cell phenotypes and functions, and thus giving medical materials certain unique biological functions. This method of modifying the physical morphology of material surfaces has the characteristics of high safety, long duration, and small side effects on tissues compared to chemical methods such as grafting chemical molecules. Studies have shown that constructing a honeycomb titanium dioxide microporous structure on the surface of metal titanium can regulate the polarization behavior of macrophages and promote the bone integration of titanium [Zhu et al., Science Advances 2021; 7:eabf6654]. In the field of industrial photocatalysis, the honeycomb microporous structure on the surface of solid catalytic materials can greatly improve the photocatalytic performance due to its larger specific surface area and reactive sites.

[0003] Although high-precision microstructures can be processed on the surface of solid substrates using advanced processing technologies such as imprinting, photolithography, focused ion beam etching, and electron beam etching, the widespread application of these processing technologies is severely limited by processing area, processing efficiency, process cost, substrate selectivity, etc. Constructing a microsphere array on the surface of a solid substrate as a template for subsequent processing is the simplest and most effective method for constructing microstructures of different morphologies. If the microspheres can spontaneously form different structures in a self-assembled manner, the construction cost of the microstructure on the surface of the solid substrate can be further greatly reduced. Therefore, preparing a self-assembled microsphere template on the surface of a solid substrate is the key to constructing structures of different morphologies. Under appropriate assembly conditions, the microspheres self-assemble into a layer of tightly arranged single-layer microsphere film under the influence of gravity, capillary force, van der Waals force, and electrostatic force. At present, the method for preparing a tightly arranged ordered microsphere template on the surface of a solid substrate is relatively mature, but the method for preparing a dispersed and disordered microsphere template is rarely reported. Therefore, how to prepare a disordered microsphere template with controllable density and uniform dispersion on the surface of a solid substrate is currently a major technical problem. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for preparing a disorderly dispersed microsphere template on the surface of a solid substrate and its application.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] The first aspect of the present invention provides a method for preparing a disorderly dispersed microsphere template on the surface of a solid substrate, the method comprising: uniformly mixing large-sized microspheres and small-sized microspheres of different sizes; constructing a single-layer microsphere film on the surface of the solid substrate by self-assembly technology; removing the small-sized microspheres by etching technology, thereby obtaining a uniformly dispersed, density-controllable, and disorderly arranged large-sized microsphere template on the surface of the solid substrate. In the method provided by the present invention, in the single-layer microsphere film constructed by self-assembly technology, the small-sized microspheres are closely arranged and the large-sized microspheres are randomly separated, so that the large-sized microspheres are dispersed and disorderly arranged on the surface of the solid substrate.

[0007] Furthermore, the step of constructing a single-layer microsphere film on the surface of a solid substrate by self-assembly technology includes: directly self-assembling the large-sized microspheres and the small-sized microspheres on the surface of the solid substrate to obtain a single-layer microsphere film on the surface of the solid substrate.

[0008] Furthermore, in the step of constructing a single-layer microsphere film on the surface of a solid substrate by self-assembly technology, the method includes: firstly self-assembling the large-sized microspheres and the small-sized microspheres on the surface of a solution, and then transferring the single-layer microsphere film to the surface of a solid substrate to obtain a single-layer microsphere film on the surface of the solid substrate.

[0009] Furthermore, in the step of uniformly mixing the large-sized microspheres and the small-sized microspheres of different sizes, the separation distance of the large-sized microspheres in the single-layer microsphere film is regulated by controlling the mixing ratio of the large-sized microspheres and the small-sized microspheres. That is, the density of the large-sized microspheres is controllable. For example, when the amount of large-sized microspheres added remains unchanged, the more small-sized microspheres are added, the larger the separation distance of the large-sized microspheres.

[0010] Furthermore, the self-assembly technology is one or more of dip coating, spin coating, electric field assisted self-assembly, evaporation induced self-assembly and slope induced self-assembly transfer.

[0011] Furthermore, the etching technology is plasma etching, electron beam etching or focused ion beam etching.

[0012] Furthermore, the diameter of the large-sized microspheres is 1 μm to 10 μm, and the diameter of the small-sized microspheres is 0.1 μm to 2 μm. It should be noted that the diameters of the large-sized microspheres and the small-sized microspheres can overlap in the range of values, but the size gap between the large-sized microspheres and the small-sized microspheres should be widened as much as possible during the selection process.

[0013] The second aspect of the present invention provides a uniformly dispersed, density-controllable, disorderly arranged large-sized microsphere template on the surface of a solid substrate, obtained by the method for preparing a disorderly dispersed microsphere template on the surface of a solid substrate as described above.

[0014] The third aspect of the present invention provides the application of the large-size microsphere template that is uniformly dispersed, density-controllable, and disorderly arranged on the surface of a solid substrate as described above in the field of surface modification of biomedical materials and in the study of the effects of porous microstructures of different densities on cell or bacterial behavior and function.

[0015] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages:

[0016] 1. The method of the present invention solves the technical problem of constructing a microsphere template with controllable density and disorderly dispersion on the surface of a solid substrate;

[0017] 2. Since the method of the present invention is based on self-assembly technology, it is possible to prepare microsphere templates on the surface of a solid substrate at low cost, over a large area and with high efficiency;

[0018] 3. The method of the present invention can simply and conveniently control the density of the microsphere template;

[0019] 4. The technologies used in the method of the present invention are common technologies that have been maturely applied, the process is simple and the cost is low, and it is suitable for batch and industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0021] Figure 1a It is an optical microscope picture of a microsphere film (Ti100) on the surface of a titanium sheet prepared by using a microsphere mixture solution in which 2 μm microspheres account for 100% in Example 2;

[0022] Figure 1b It is an optical microscope picture of a microsphere film (Ti80) on the surface of a titanium sheet prepared by using a microsphere mixture solution in which 2 μm microspheres account for 80% in Example 2;

[0023] Figure 1c It is an optical microscope picture of a microsphere film (Ti50) on the surface of a titanium sheet prepared by using a microsphere mixture solution in which 2 μm microspheres account for 50% in Example 2;

[0024] Figure 1dIt is an optical microscope picture of a microsphere film (Ti20) on the surface of a titanium sheet prepared by using a microsphere mixture solution in which 2 μm microspheres account for 20% in Example 2;

[0025] Figure 2a is a scanning electron microscope image of the Ti20 sample in Example 3 before plasma etching;

[0026] Figure 2b is a scanning electron microscope image of the Ti20 sample in Example 3 after plasma etching;

[0027] Figure 3a is a scanning electron microscope picture of the Ti100S sample in Example 5; the left side is a picture taken at low magnification, and the right side is a picture taken at high magnification;

[0028] Figure 3b is a scanning electron microscope picture of the Ti80S sample in Example 5; the left side is a picture taken at low magnification, and the right side is a picture taken at high magnification;

[0029] Figure 3c The scanning electron microscope image of the Ti50S sample in Example 5; the left side is a photo taken at low magnification, and the right side is a photo taken at high magnification;

[0030] Figure 3d is a scanning electron microscope picture of the Ti20S sample in Example 5; the left side is a picture taken at low magnification, and the right side is a picture taken at high magnification;

[0031] Figure 4 It is a schematic diagram of a tightly ordered monolayer of densely packed microspheres formed by self-assembly on the surface of a solid substrate;

[0032] Figure 5 After reducing the density of microspheres, the microspheres still tend to partially aggregate together rather than being evenly dispersed on the surface of the solid substrate;

[0033] Figure 6 The present invention provides a flow chart of a method for preparing a disorderly dispersed microsphere template on a solid substrate surface. DETAILED DESCRIPTION

[0034] The inventors have found that the key to preparing microstructures on the surface of solid substrates lies in the design and construction of templates, and currently most microstructures are prepared using self-assembled microspheres as templates. Therefore, the assembly method of microspheres, order and other parameters are key factors that determine the morphology and order of the obtained microstructures. The techniques for assembling two-dimensional monolayer microspheres on the surface of solid substrates include dip coating, spin coating, electric field assisted self-assembly, evaporation induced self-assembly and slope induced self-assembly transfer. These techniques can be used to prepare a tightly and orderly monolayer densely packed microsphere template on the surface of a solid substrate, such as Figure 4 However, it is difficult to obtain the desired effect when using these technologies to prepare a uniformly dispersed, density-controlled, and disorderly arranged single-layer microsphere template. This is because when the density of the microspheres is reduced to make them randomly dispersed on the surface of the solid substrate, the microspheres still tend to aggregate together due to the surface tension of the liquid and the charge interaction between the microspheres. Figure 5 Therefore, it is difficult to make the microspheres spontaneously form a uniformly dispersed, density-controllable, and disorderly arranged single-layer microsphere template on the surface of a solid substrate by self-assembly.

[0035] In order to solve this problem, the present invention proposes to add smaller microspheres to the self-assembled microspheres. After the two sizes of microspheres are evenly mixed, a self-assembly operation is performed, and the small-sized microspheres are closely arranged and the large-sized microspheres are randomly separated. By adjusting the addition ratio of the two different-sized microspheres, the spacing between the large-sized microspheres can be adjusted, that is, the density of the large-sized microspheres can be adjusted. Then, the small-sized microspheres are removed by etching technology, and a uniformly dispersed, density-controlled, and disorderly arranged microsphere template can be obtained on the surface of the solid substrate.

[0036] The present invention introduces a method and application for preparing a uniformly dispersed, disordered, and density-controllable microsphere template on a solid substrate surface over a large area and at a low cost. The method uses two microspheres of different sizes, which are evenly mixed in different proportions, and then a single-layer microsphere film composed of a mixed arrangement of large and small microspheres of two sizes is constructed on the surface of a solid substrate by self-assembly. In the microsphere film, small-sized microspheres are closely arranged, and large-sized microspheres are randomly separated from each other, so that the large-sized microspheres can be stably, disorderly, and dispersedly distributed in the film. Subsequently, the smaller-sized microspheres are removed by etching technology, and the remaining larger-sized microspheres form a disordered and dispersed microsphere template on the surface of the solid substrate. The separation density of the large-sized microspheres can be controlled by adjusting the addition ratio of the large and small microspheres.

[0037] The first aspect of the present invention provides a method for preparing a disorderly dispersed microsphere template on the surface of a solid substrate, the method comprising: uniformly mixing large-sized microspheres and small-sized microspheres of different sizes; constructing a single-layer microsphere film on the surface of the solid substrate by self-assembly technology; and removing the small-sized microspheres by etching technology, thereby obtaining a uniformly dispersed, density-controllable, and disorderly arranged large-sized microsphere template on the surface of the solid substrate.

[0038] The second aspect of the present invention provides a large-sized microsphere template uniformly dispersed on the surface of a solid substrate with controllable density and disordered arrangement, obtained by the method for preparing a disorderly dispersed microsphere template on the surface of a solid substrate as described above.

[0039] The third aspect of the present invention provides the application of the large-size microsphere template as described above, which is uniformly dispersed, density-controllable, and disorderly arranged on the surface of a solid substrate, in the field of surface modification of biomedical materials and in the study of the effects of porous microstructures of different densities on cell or bacterial behavior and function.

[0040] The present invention is described in detail below in conjunction with specific implementation modes.

[0041] In the following examples, large and small microspheres are selected from polystyrene (PS) microspheres of two sizes, 2 μm and 0.1 μm, respectively, and the solid substrate is selected from pure titanium sheet. The construction technology of the microsphere film is to transfer it to the surface of the solid substrate by using the immersion pulling method after liquid surface self-assembly, and the etching technology is plasma etching, thereby proving the feasibility of the method described in the present invention. In addition, this example will further process the prepared microsphere template to confirm the feasibility of using the microsphere template to construct different microstructures on the surface of the solid substrate.

[0042] Example 1

[0043] A titanium sheet with a diameter of 10 mm and a thickness of 2 mm was polished with 800 mesh, 1200 mesh, 2000 mesh and 4000 mesh sandpaper in sequence. Then, acetone, alcohol and deionized water were ultrasonically cleaned for 10 minutes in sequence. The titanium sheet obtained after the pretreatment was used as the solid substrate in this embodiment. In addition, a plasma cleaning machine can also be used to treat the titanium sheet to improve the hydrophilicity of the titanium sheet, so as to facilitate the subsequent transfer of microspheres on the surface of the titanium sheet.

[0044] Example 2

[0045] Take an aqueous suspension containing 10 wt% of 0.1 μm and 2 μm PS microspheres and mix them with an equal volume of ethanol. Then use an ultrasonic cleaner to ultrasonically disperse for 30 minutes. The ultrasonically dispersed 0.1 μm and 2 μm PS microspheres are mixed in different volume ratios of 0:1, 1:4, 1:1, and 4:1, and then vortexed and ultrasonically dispersed again for 30 minutes to make them evenly mixed. The proportion of 2 μm microspheres in the microsphere mixture is recorded as 100%, 80%, 50%, and 20%.

[0046] Take a clean glass slide, immerse one side in a culture dish filled with distilled water, and support the other side so that its inclination angle is about 50 degrees. Then slowly drip the PS microsphere mixture of different proportions onto the tilted glass slide. After the microsphere mixture contacts the distilled water surface, it self-assembles into a single-layer microsphere film evenly on the water surface under the action of Brownian motion and surface tension. Then immerse the bottom of the culture dish in an ultrasonic cleaner for 5 minutes to make the large and small microspheres more evenly dispersed. Finally, use tweezers to immerse the titanium sheet obtained in Implementation Case 1 below the water surface along the side of the culture dish. After transferring the titanium sheet to the bottom of the single-layer microsphere film, pull the titanium sheet vertically upward, so that the microsphere film on the liquid surface is transferred to the surface of the titanium sheet by this immersion-pulling method. Then lay the titanium sheet flat and dry it at room temperature. The titanium sheet samples obtained are named Ti100, Ti80, Ti50 and Ti20 according to the proportion of 2μm microspheres in the microsphere mixture.

[0047] Use an optical microscope to observe the distribution of microspheres on the surface of the titanium sheet (the optical microscope can only see large-sized microspheres with a diameter of 2 μm, but cannot see small-sized microspheres with a diameter of 0.1 μm). Figure 1a As shown in Figure 5-d, with the decrease in the proportion of large-sized (2 μm) microspheres in the microsphere mixture, the density of large-sized microspheres on the surface of the titanium sheet gradually decreases, and its distribution state gradually evolves from a highly ordered distribution (Ti100) to a disordered dispersed distribution (Ti80, Ti50 and Ti20).

[0048] Example 3

[0049] Use plasma etching technology to remove the small-sized microspheres in the microsphere film constructed on the surface of the titanium sheet in Example 2. Place the sample in the sample chamber of the plasma etcher and evacuate it. Then set the RF power supply to 100W, introduce oxygen to make the pressure in the sample chamber reach about 0.4mbar, activate plasma etching for 5-10min after stabilization, remove 0.1μm PS microspheres, and retain 2μm PS microspheres. The samples Ti100, Ti80, Ti50 and Ti20 obtained after plasma etching are marked as Ti100P, Ti80P, Ti50P and Ti20P respectively. Figure 2a The figure shows the morphology of the microsphere film on the surface of the Ti20 sample before plasma etching, taken by scanning electron microscope. It can be seen from the figure that the large-sized microspheres are randomly and disorderly distributed on the surface, while the small-sized microspheres are closely arranged between the large-sized microspheres. Figure 2b The figure shows the morphology of the microsphere film on the surface of the Ti20 sample after plasma etching, taken by a scanning electron microscope. It can be seen from the figure that after etching, there are basically no small-sized microspheres on the surface of the titanium sheet, and the diameter of the large-sized microspheres has basically not changed significantly after the treatment. Therefore, through the above treatment, a density-controllable and disorderly dispersed microsphere template was successfully prepared on the surface of the titanium sheet.

[0050] Example 4

[0051] The microsphere template prepared in the above example is further processed to construct disordered microstructures with different densities on the surface of the titanium sheet.

[0052] Use 0.05MH2SO4 solution to prepare 0.5wt% titanium sulfate (Ti(SO4)2) solution; add 120μL titanium isopropoxide (TTIP) to 10mL anhydrous ethanol, blow and mix and shake for 30min, then add 100μL of pure water and 2mL isopropanol mixture, continue to shake and mix for 30min, adjust the pH to 3-4 with a few drops of concentrated hydrochloric acid, and mix to obtain titanium dioxide hydrosol precursor. Take 20μL of the prepared Ti(SO4)2 solution or titanium dioxide hydrosol precursor and add it dropwise on the microsphere templates of different densities prepared in Example 3, and dry it at room temperature.

[0053] Example 5

[0054] After the titanium sheet with Ti(SO4)2 solution or hydrosol precursor solution added was dried, it was placed in an oven and heated at 50℃ for 2h, and then the sample was placed in a muffle furnace, heated to 400℃~500℃ and kept for 2~3 hours. The high temperature treatment here can generate a titanium dioxide film layer from Ti(SO4)2 or hydrosol precursor on the surface of the sample, and on the other hand, the 2μm PS microsphere template can be removed by high temperature. Then, the furnace was cooled to room temperature, and a uniformly distributed disordered TiO2 porous structure with different densities was obtained. The porous samples obtained after the above treatment of samples Ti100P, Ti80P, Ti50P and Ti20P were marked as Ti100S, Ti80S, Ti50S and Ti20S, respectively. The surface morphology of the obtained structure was observed using a scanning electron microscope. As shown in Figure X, a porous microstructure with different pore densities was successfully constructed on the surface of the titanium sheet. The pores in the microstructure are what remain after the microsphere template is removed, so the density and distribution of the microspheres in the microsphere template determine the density and distribution of the pores in the microstructure. Figure 3a to Figure 3d It can be seen that with the decrease in the addition ratio of 2 μm microspheres, the density of the pores in the prepared microstructure gradually decreases, and the microstructure gradually evolves from a highly ordered state (Ti100S) to a randomly disordered state (Ti80S, TI50S and TI20S).

[0055] It can be seen that the technical solution of the present invention is mainly divided into two parts: 1. Evenly mix microspheres of different sizes (theoretically, the diameter difference should be large, such as 0.1μm and 2μm); 2. Construct a single-layer microsphere film on the surface of a solid substrate by self-assembly. It can be directly self-assembled on the surface of a solid substrate, such as using spin coating, evaporation-induced self-assembly, etc.; it can also be self-assembled on the surface of a solution first, and then the single-layer microsphere film is transferred to the surface of a solid substrate. The small-sized microspheres in the microsphere film are closely arranged, and the large-sized microspheres are randomly separated from each other, so that the large-sized microspheres are dispersed and disorderly arranged on the surface of the solid substrate. The separation distance of the large-sized microspheres can be controlled by adjusting the mixing ratio of large and small microspheres. 3. Use etching technology to remove the small-sized microspheres, leaving a uniformly dispersed, density-controllable, and disorderly arranged large-sized microsphere template. The flow chart of this method is as follows Figure 6 shown.

[0056] In summary, the present invention provides a method for constructing a density-controllable and disorderly dispersed microsphere template on the surface of a solid substrate over a large area and at a low cost. By adding smaller microspheres to the previously self-assembled microspheres, the small-sized microspheres randomly separate the large-sized microspheres during the self-assembly process, and then removing the small-sized microspheres by etching, a uniformly dispersed, density-controllable, and disorderly arranged large-sized microsphere template is obtained on the surface of the solid substrate. It can be used for surface modification of biomedical materials to improve the service effect of the materials, or for some basic research, such as the study of the effects of porous microstructures of different densities on the behavior and function of cells or bacteria. The template preparation method provided by the present invention can also be applied to industrial manufacturing, such as the production of photolithography templates.

[0057] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present application. Any person skilled in the art can make their own changes and modifications without departing from the spirit and scope of the present application, so the scope of protection of the present application shall be based on the scope defined in the claims.

Claims

1. A method for preparing a randomly dispersed microsphere template on a solid substrate surface, characterized in that: The method comprises: uniformly mixing large-sized microspheres and small-sized microspheres of different sizes; constructing a single-layer microsphere film on the surface of a solid substrate by a self-assembly technique; removing the small-sized microspheres by an etching technique, thereby obtaining a uniformly dispersed, density-controllable, and disorderly arranged large-sized microsphere template on the surface of the solid substrate; The step of uniformly mixing the large-sized microspheres and the small-sized microspheres of different sizes includes: regulating the separation distance of the large-sized microspheres in the single-layer microsphere film by controlling the mixing ratio of the large-sized microspheres and the small-sized microspheres; when the amount of the large-sized microspheres added remains unchanged, the more small-sized microspheres are added, the larger the separation distance of the large-sized microspheres is; In the single-layer microsphere film constructed by self-assembly technology, small-sized microspheres are closely arranged and large-sized microspheres are randomly separated, so that the large-sized microspheres are dispersed and disorderly arranged on the surface of the solid substrate; The self-assembly technique is one or more of dip coating, spin coating, electric field assisted self-assembly, evaporation induced self-assembly and slope induced self-assembly transfer; the etching technique is plasma etching, electron beam etching or focused ion beam etching; The diameter of the large-sized microspheres is 2 μm to 10 μm, and the diameter of the small-sized microspheres is 0.1 μm to 2 μm.

2. The method for preparing a randomly dispersed microsphere template on a solid substrate surface according to claim 1, characterized in that: The step of constructing a single-layer microsphere film on the surface of a solid substrate by self-assembly technology includes: directly self-assembling the large-sized microspheres and the small-sized microspheres on the surface of the solid substrate to obtain a single-layer microsphere film on the surface of the solid substrate.

3. The method for preparing a randomly dispersed microsphere template on a solid substrate surface according to claim 1, characterized in that: The step of constructing a single-layer microsphere film on the surface of a solid substrate by self-assembly technology includes: firstly self-assembling the large-sized microspheres and the small-sized microspheres on the surface of a solution, and then transferring the single-layer microsphere film to the surface of a solid substrate to obtain a single-layer microsphere film on the surface of the solid substrate.

4. A large-sized microsphere template uniformly dispersed, with controllable density and disorderly arranged on the surface of a solid substrate, obtained by the method for preparing a disorderly dispersed microsphere template on the surface of a solid substrate as claimed in any one of claims 1 to 3.

5. Application of the large-size microsphere template as claimed in claim 4, which is uniformly dispersed, density-controllable and disorderly arranged on the surface of a solid substrate, in the field of surface modification of biomedical materials and in the research field of the effects of porous microstructures of different densities on cell or bacterial behavior and function.

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