Method for preparing curved surface structure through self-driven forming of micro-nano structure induced fluid interface and application of method

Abstract

The invention provides a method for preparing a curved surface structure through self-driven forming of a micro-nano structure induced fluid interface and application of the method, and belongs to the field of micro-nano manufacturing of multifunctional surfaces. According to the method, a natural ice piton structure forming process and forming characteristics are taken as a bionic prototype, micron-sized array through holes are prepared in a template, and an array arrangement curved surface structure is formed on the other sides of the through holes through self-driving of photosensitive resin under the action of gravity, surface tension and external pressure; the array curved surface structure can show excellent resistance reduction, antifouling and anti-icing functions and the like; under the action of gravity and surface tension, fluid (liquid resin) is directly induced to conduct behavior regulation and control on an interface, an ultraviolet lamp is used for conducting curing forming on a complex curved surface structure, and controllable preparation of the complex curved surface structure is achieved. The prepared curved surface structure is smoother, the surface roughness is smaller, meanwhile, a consistent array structure is achieved, and the surface roughness of a single curved surface structure is smaller than 2 micrometers.

Description

Technical Field

[0001] The present invention relates to the field of micro-nano manufacturing multifunctional surfaces, and in particular to a method for preparing a curved surface structure by inducing self-driven molding of a fluid interface using a micro-nano structure and its application. Background Art

[0002] In billions of years of evolution and natural selection, organisms have evolved unique physiological functions and surface structural features to adapt to changes in the complex external environment. Learning from nature and using the unique material properties and structural characteristics of organisms as bionic prototypes can provide theoretical references and innovative basis for solving actual technical problems in engineering. For example, the super-hydrophobic surface based on the micro-nanopapillary structure of the lotus leaf surface and the bionic drag-reducing non-smooth surface based on the structural characteristics of shark epidermis shield scales provide feasible references for the preparation of bionic functional surfaces.

[0003] Taking the unique structural characteristics and material properties of natural organisms as the starting point, the preparation of functionalized bionic surfaces has become one of the current research hotspots of smart skins or functional coatings. How to achieve controllable preparation of bionic structures / materials through preparation processes or precision manufacturing methods is one of the key factors affecting the successful application of bionic functional surfaces in the engineering field. With the continuous development of manufacturing processes and the continuous maturity of technology, it has been possible to successfully prepare functionalized bionic micro-nanostructure surfaces using multiple materials and multiple processes, such as lithography, precision machining, 3D precision printing, laser processing, and nano-imprinting. The above-mentioned preparation processes or methods have their own advantages and disadvantages in the preparation of micro-nano structures, but there are limitations that cannot be ignored in the preparation of complex micro-nano surfaces.

[0004] The photolithography process has significant advantages in the preparation of complex micro-nano structures. Its high precision and excellent molding quality enable it to prepare multi-level complex micro-nano structures. However, photolithography technology faces great challenges in the preparation of curved surface structures, mainly due to the limitation of the optical path, resulting in low feasibility. In addition, the photolithography process is costly, has a long cycle, and is difficult to prepare complex curved surface structures. Although precision machining can process micro-nano structures, due to the limitations of machining accuracy and tool path, the surface is prone to step-like roughness when machining curved surface structures, which is difficult to meet high-precision requirements. Although ultra-precision 3D printing technology can achieve the configuration of complex curved surfaces, due to the limitation of the accuracy of moving parts, the surface roughness of the machined curved surface structure is still large and cannot achieve the ideal effect. Although laser etching can control the machining path to prepare a curved surface structure with a certain curvature, its surface roughness is the largest among the above-mentioned processes, and the molding quality is low. Nanoimprinting technology relies on the preparation of negative templates, resulting in high molding costs, long cycles, and limited machining accuracy for curved surface structures. In nature, many special structures on biological surfaces are not linear structures, but the structural parameters show gradient changes in space. Their special micro-nano structures make the biological epidermis show excellent environmental adaptability, such as the water collection function of the convex structure of desert beetles and the self-cleaning function of the micro-nano convex structure on the surface of lotus leaves. In order to prepare complex curved micro-nano structures, the Shinill research group of Yonsei University in South Korea used laser interference lithography to produce a metal anti-biological contamination surface with a hierarchical morphology and nanostructures on curved micro-grains. However, this preparation process is complicated and costly, and it cannot prepare complex curved surface structures with large curvatures.

[0005] Therefore, providing a preparation method with simple process, low cost and the ability to quickly prepare complex curved surface structures has become a technical problem to be urgently solved in the field. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing a curved surface structure by inducing fluid interface self-driven forming using micro-nano structures and its application. The method provided by the present invention has a simple process flow and low cost, and can prepare a complex curved surface structure with extremely low roughness of a single curved surface structure.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing a curved surface structure by inducing fluid interface self-driven molding using a micro-nano structure, comprising the following steps:

[0009] (1) preparing a micrometer-scale array of through holes on a template to obtain a template for inducing self-driven flow of a photocurable resin;

[0010] (2) pouring liquid resin on the upper surface of the template for inducing self-driven flow of photocurable resin obtained in step (1), and performing ultraviolet light curing when the liquid resin gathers into droplets on the lower surface of the template for inducing self-driven flow of photocurable resin to obtain a surface with a curved structure.

[0011] Preferably, the template in step (1) is an opaque template, and the thickness of the template is 0.5 to 2 mm.

[0012] Preferably, the template in step (1) is a metal template.

[0013] Preferably, the micrometer-scale array through holes in step (1) are of regular shape.

[0014] Preferably, the micrometer-scale array through holes in step (1) are circular, triangular, rectangular, pentagonal, pentagonal or hexagonal.

[0015] Preferably, the liquid resin in step (2) is a photosensitive liquid resin.

[0016] Preferably, in the step (2), the time for the liquid resin to aggregate into droplets on the lower surface of the template for inducing self-driven flow of the photocurable resin is 0.5 to 6 seconds.

[0017] Preferably, in step (2), the power of UV curing is 100 to 300 W, and the time of UV curing is 10 to 25 s.

[0018] Preferably, the UV curing in step (2) is performed using a UV curing lamp; the UV curing lamp is placed 5 to 20 cm below the template for inducing self-driven flow of the photocurable resin.

[0019] The present invention provides the application of a surface with a curved structure obtained by the method described in the above technical solution in smart skin and a coating for reducing the friction resistance of a solid-liquid interface.

[0020] The present invention provides a method for preparing a curved surface structure by inducing self-driven forming of a fluid interface using a micro-nano structure, comprising the following steps: (1) preparing a micron-level array of through holes on a template to obtain a template for inducing self-driven flow of a photocurable resin; (2) pouring liquid resin on the upper surface of the template for inducing self-driven flow of a photocurable resin obtained in step (1), and performing ultraviolet light curing when the liquid resin gathers into droplets on the lower surface of the template for inducing self-driven flow of a photocurable resin, thereby obtaining a surface with a curved surface structure. The present invention takes the formation process and formation characteristics of ice cones in nature as a bionic prototype, and first prepares a micron-level array of through holes on the template, so that when the liquid resin flows in the through holes under the synergistic effect of gravity and surface tension, it is ultraviolet cured when it gathers into droplets on the lower surface of the template for inducing self-driven flow of a photocurable resin, thereby obtaining a surface with a complex curved surface structure. The present invention directly induces the fluid (liquid resin) interface to perform self-driven molding under the synergistic effect of gravity and surface tension, and uses ultraviolet lamps to perform curing molding of complex curved surface structures, thereby achieving controllable preparation of complex curved surface structures; the curved surface structure prepared by the present invention is smoother, has a smaller surface roughness, and has a consistent array structure. The results of the embodiment show that the surface roughness of the curved surface structure prepared by the present invention is less than 2μm. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure of a template for inducing self-driven flow of a photocurable resin prepared by the present invention;

[0022] Figure 1 In the figure, 1 is the micrometer-scale array through-hole, and 2 is the template;

[0023] Figure 2 A structural cross-sectional view of a template for inducing self-driven flow of a photocurable resin prepared by the present invention;

[0024] Figure 2 In the figure, 1 is a micrometer-scale array through hole;

[0025] Figure 3 A schematic diagram of a surface with a curved structure prepared in the present invention;

[0026] Figure 3 In the figure, 3 is liquid resin and 4 is UV curing lamp. DETAILED DESCRIPTION

[0027] The present invention provides a method for preparing a curved surface structure by inducing fluid interface self-driven molding using a micro-nano structure, comprising the following steps:

[0028] (1) preparing a micrometer-scale array of through holes on a template to obtain a template for inducing self-driven flow of a photocurable resin;

[0029] (2) pouring liquid resin on the upper surface of the template for inducing self-driven flow of photocurable resin obtained in step (1), and performing ultraviolet light curing when the liquid resin gathers into droplets on the lower surface of the template for inducing self-driven flow of photocurable resin to obtain a surface with a curved structure.

[0030] The present invention prepares micrometer-level array through holes on a template to obtain a template for inducing self-driven flow of photocurable resin.

[0031] In the present invention, the template is preferably an opaque template, more preferably a metal template, and further preferably a polished brass template, a stainless steel template or an aluminum alloy template. The present invention has no special limitation on the method for preparing the self-driven template, which can be a 3D printed template or a template obtained by other methods. The present invention uses an opaque template to prepare a curved surface structure, which can avoid the resin from being solidified due to ultraviolet light during the process of just pouring or passing through the microporous structure, thereby causing preparation failure.

[0032] In the present invention, the thickness of the template is preferably 0.5-2 mm. By controlling the thickness of the template, the present invention can ensure that the resin can smoothly pass through the through hole after pouring, thereby inducing flow on the lower side to form a droplet-shaped curved surface structure.

[0033] In the present invention, the micrometer-scale array through holes are preferably regular in shape. The present invention has no particular limitation on the specific shape of the regular shape, and it can be a regular shape well known to those skilled in the art. As an embodiment, the regular shape can be circular, triangular, rectangular, pentagonal, pentagonal or hexagonal; the side length or diameter of the regular shape can be 500 μm, 600 μm, 700 μm, 800 μm, 900 μm or 1000 μm.

[0034] In the present invention, the spacing between two through holes in the micrometer-level array through hole is preferably ≤0.5D, where D is the maximum distance between two points of a single through hole. The present invention can give the prepared array complex curved surface structure special functions by preparing micrometer-level array through holes and controlling their parameters.

[0035] The present invention has no particular limitation on the specific method for preparing the micron-scale array through holes. The method well known to those skilled in the art can be used to prepare the micron-scale array through holes as long as the size and shape of the micron-scale array through holes meet the requirements.

[0036] After obtaining a template for inducing self-driven flow of photocurable resin, the present invention pours liquid resin on the upper surface of the template for inducing self-driven flow of photocurable resin, and when the liquid resin gathers into droplets on the lower surface of the template for inducing self-driven flow of photocurable resin, ultraviolet light curing is performed to obtain a surface with a curved surface structure. The present invention allows the liquid resin to flow in the through hole under the synergistic effect of gravity and surface tension, and when it gathers into droplets on the lower surface of the template, ultraviolet light curing is performed to obtain a surface with a complex curved surface structure.

[0037] In the present invention, the liquid resin is preferably a photosensitive liquid resin, and more preferably a rigid standard photosensitive resin suitable for ultraviolet light with a wavelength of 405 nm. As an embodiment of the present invention, the liquid resin can be Anycubic / Zongweicubic rigid standard photosensitive resin produced by Shenzhen Zongweicubic Technology Co., Ltd. In the present invention, the pouring speed of the liquid resin is preferably 1 to 5 g / s. The present invention can ensure that the liquid resin is fully spread on the template by controlling the pouring speed of the liquid resin.

[0038] In the present invention, the pouring of the liquid resin is preferably carried out in a container. The present invention has no particular limitation on the type and shape of the container, as long as it has windproof capability. As an embodiment, the container is preferably a cylindrical container of equal diameter. The present invention can avoid the influence of external gas flow on air pressure by pouring the liquid resin in the container.

[0039] In the present invention, the time for the liquid resin to aggregate into droplets on the lower surface of the template for inducing self-driven flow of the photocurable resin is preferably 0.5 to 6 seconds. The present invention can control the size of the droplets by controlling the time for the liquid resin to aggregate into droplets.

[0040] As an embodiment, the time for the liquid resin to aggregate into droplets on the lower surface of the template for inducing self-driven flow of the photocurable resin may be 0.5 s, 1 s, 2 s, 3 s, 4 s, 5 s or 6 s.

[0041] In the present invention, the power of the ultraviolet light curing is preferably 100 to 300 W; the time of the ultraviolet light curing is preferably 10 to 25 seconds. The present invention can ensure that the liquid resin is completely cured by controlling the parameters of the ultraviolet light curing.

[0042] As an implementation manner, the power of the UV light curing may be 100 W, 150 W, 200 W, 250 W or 300 W; the time of the UV light curing may be 10 s, 15 s, 20 s or 25 s.

[0043] In the present invention, the UV curing method is preferably to use a UV curing lamp for UV curing; the UV curing lamp is preferably placed 5 to 20 cm below the template for inducing self-driven flow of the photocurable resin, preferably 10 to 15 cm.

[0044] The flowchart of the method for preparing a curved surface structure by inducing a fluid interface with a micro-nano structure provided by the present invention is as follows: Figures 1 to 3 shown.

[0045] Figure 1 The schematic diagram of the structure of the template for inducing the self-driven flow of the photocurable resin prepared by the present invention is as follows: Figure 2 The structural cross-sectional view of the template for inducing self-driven flow of photocurable resin prepared by the present invention, Figure 3 Schematic diagram of a surface with a curved structure prepared according to the present invention. Figure 1 In the figure, 1 is the micrometer-scale array through-hole, and 2 is the template; Figure 2 In the figure, 1 is a micrometer-scale array through hole; Figure 3 In the figure, 3 is liquid resin and 4 is UV curing lamp. Figures 1 to 3 It can be seen that the present invention takes the formation process and characteristics of the ice cone structure in nature as a bionic prototype, prepares micron-scale array through holes on the template, and uses photosensitive resin to precisely control gravity, surface tension and external pressure, so that the photocurable material is self-driven on the other side of the through hole to form an array-arranged curved surface structure. The array curved surface structure can exhibit excellent drag reduction, anti-fouling and anti-icing functions; by directly inducing the fluid (liquid resin) to regulate its behavior at the interface under the action of gravity and surface tension, and using ultraviolet lamps to perform curing and molding of complex curved surface structures, controllable preparation of complex curved surface structures is achieved; the curved surface structure prepared by the present invention is smoother, has a smaller surface roughness, and has a consistent array structure.

[0046] The present invention also provides the application of the surface with curved structure obtained by the method described in the above technical solution in smart skin and coating for reducing friction resistance at solid-liquid interface.

[0047] The surface of the curved structure obtained by the present invention is smoother, has less surface roughness, and has a consistent array structure.

[0048] The present invention has no particular limitation on the specific manner of the application, and any application manner familiar to those skilled in the art may be used.

[0049] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] Example 1

[0051] A method for preparing a curved surface structure by inducing fluid interface self-driven molding through micro-nano structures comprises the following steps:

[0052] (1) preparing a micrometer-scale array through hole on a polished brass template with a thickness of 2 mm to obtain a template for inducing self-driven flow of a photocurable resin; the micrometer-scale array through hole is circular in shape, the diameter of the micrometer-scale array through hole is 300 μm, and the center distance between two adjacent through holes is 500 μm;

[0053] (2) The self-driving template obtained in step (1) is placed in a cylindrical container of equal diameter, and a UV curing lamp is placed 10 cm below the template for inducing self-driven flow of photocurable resin, and then liquid resin is poured on the upper surface of the template for inducing self-driven flow of photocurable resin. The liquid resin flows in the through hole under the synergistic effect of gravity and surface tension, and UV curing is performed when the liquid resin gathers into droplets on the lower surface of the template for inducing self-driven flow of photocurable resin to obtain a surface with a complex curved surface structure; the liquid resin is Anycubic / Zongweicubic rigid standard photosensitive resin produced by Shenzhen Zongweicubic Technology Co., Ltd.; the pouring speed of the liquid resin is 5g / s; the time for the liquid resin to gather into droplets on the lower surface of the template for inducing self-driven flow of photocurable resin is 3s; the power of the UV curing is 200W, and the time of the UV curing is 20s.

[0054] Example 2

[0055] The shape of the micrometer-scale array through hole is square, the side length of the micrometer-scale array through hole is 300 μm, and the center distance between two adjacent through holes is 500 μm;

[0056] Other conditions are the same as in Example 1.

[0057] Example 3

[0058] The shape of the micrometer-scale array through hole is a regular hexagon, the side length of the micrometer-scale array through hole is 300 μm, and the center distance between two adjacent through holes is 800 μm;

[0059] Other conditions are the same as in Example 1.

[0060] The surface structures with complex curved surface structures obtained in Examples 1 to 3 were observed using a laser confocal microscope and a three-dimensional white light interferometer profilometer, respectively. The surface roughness of the complex curved surface structure obtained by the method provided by the present invention was less than 1 μm.

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a curved surface structure by inducing fluid interface self-driven molding using micro-nano structures, comprising the following steps: (1) preparing a micrometer-scale array of through holes on a template to obtain a template for inducing self-driven flow of a photocurable resin; (2) pouring liquid resin on the upper surface of the template for inducing self-driven flow of photocurable resin obtained in step (1), and performing ultraviolet light curing when the liquid resin gathers into droplets on the lower surface of the template for inducing self-driven flow of photocurable resin to obtain a surface with a curved structure.

2. The method according to claim 1, characterized in that The template in step (1) is an opaque template, and the thickness of the template is 0.5 to 2 mm.

3. The method according to claim 1 or 2, characterized in that: The template in step (1) is a metal template.

4. The method according to claim 1, characterized in that: The micrometer-scale array through holes in step (1) are of regular shape.

5. The method according to claim 1 or 2, characterized in that: The micrometer-scale array through holes in step (1) are circular, triangular, rectangular, pentagonal, pentagonal or hexagonal.

6. The method according to claim 1, characterized in that The liquid resin in step (2) is a photosensitive liquid resin.

7. The method according to claim 1, characterized in that In the step (2), the time for the liquid resin to aggregate into droplets on the lower surface of the template used to induce the self-driven flow of the photocurable resin is 0.5 to 6 seconds.

8. The method according to claim 1, characterized in that In the step (2), the power of ultraviolet light curing is 100 to 300 W, and the time of ultraviolet light curing is 10 to 25 seconds.

9. The method according to claim 1, characterized in that: The UV curing in step (2) is performed using a UV curing lamp; the UV curing lamp is placed 5 to 20 cm below the template for inducing self-driven flow of the photocurable resin.

10. Application of the surface with curved structure obtained by the method according to any one of claims 1 to 9 in smart skin and coating for reducing friction resistance at solid-liquid interface.

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