Bionic composite patch for wet surface

Abstract

The invention relates to a bionic composite patch for a wet surface. The bionic composite patch comprises a bionic wet adhesion layer (1) and a sweat directional transmission layer (4) which are arranged from top to bottom, the bionic wet adhesion layer (1) is a flexible film of which the surface is provided with a multi-stage bionic microstructure array (2), and is used for forming a stable liquid bridge on a wet interface to provide tough wet adhesion force; the sweat directional transmission layer (4) is provided with a plurality of conical micropore channels (3) and is used for generating Laplace pressure difference so as to realize rapid directional transmission of liquid; the bionic wet adhesion layer (1) is provided with through holes (1.1) in gaps of the multi-stage bionic microstructure array (2), and the conical micropore channels (3) are in one-to-one correspondence with the through holes (1.1); the bionic wet adhesion layer (1) and the sweat directional transmission layer (4) are bonded to form an integrated structure. Stable adhesion can be achieved on a wet surface, and meanwhile liquid management can be conducted.

Description

Technical Field

[0001] This invention belongs to the field of functional materials and interface technology, and specifically relates to a biomimetic composite patch for damp surfaces. Background Technology

[0002] In many applications, such as wearable devices, medical dressings, and soft robot grasping, interface materials need to form a stable and reliable adhesion to damp surfaces. However, the presence of liquids (such as sweat and water films) can cause liquid to accumulate, forming a barrier water film that severely weakens the performance of most wet adhesion interfaces, leading to adhesion failure. This stems from the inherent trade-off between the functions of "reliable wet adhesion" and "liquid management."

[0003] In existing technologies, strategies to enhance wet adhesion (such as mimicking the microstructure of tree frog footpads) typically rely on forming liquid bridges, but this increases the amount of interfacial liquid and has limited drainage capacity. On the other hand, strategies for actively managing liquids (such as constructing hydrophobic channels or super-slippery surfaces) disrupt the solid-liquid contact necessary for adhesion. Traditional adhesives or biomimetic structures often act as liquid barriers, trapping liquids at the interface, leading to interface failure, decreased comfort, and even microbial growth. Therefore, developing a biomimetic interface that can overcome this inherent contradiction, providing both strong adhesion and efficient management of interfacial liquids in humid environments, is a prominent technical challenge in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a biomimetic composite patch for wet surfaces, which can achieve stable adhesion on wet surfaces and simultaneously manage liquids, in order to solve the problems of adhesion reduction, poor interface stability and limited functionality of existing adhesive materials on wet surfaces due to liquid intervention.

[0005] This invention provides a biomimetic composite patch for damp surfaces, comprising a biomimetic wet adhesion layer and a sweat directional transport layer arranged from top to bottom;

[0006] The biomimetic wet adhesion layer is a flexible film with a multi-level biomimetic microstructure array on its surface, which is used to form a stable liquid bridge at the wet interface to provide strong wet adhesion.

[0007] The sweat-directed transport layer is provided with multiple conical microporous channels to generate a Laplace pressure difference to achieve rapid directional transport of liquids;

[0008] The biomimetic wet adhesion layer has through holes in the gaps of the multi-level biomimetic microstructure array, and the conical micropore channels correspond one-to-one with the through holes to form composite pores; the biomimetic wet adhesion layer and the sweat directional transport layer are bonded to form an integral structure, which is used to maintain the dynamic balance of the interface liquid through synergistic effect.

[0009] Furthermore, the biomimetic microstructure array includes multiple micron-sized columnar arrays arranged in a hexagonal pattern. Each micron-sized columnar array includes a hexagonal frame mimicking a bee's footpad and a nano-sized concave cavity mimicking a bee's footpad. The concave cavity mimicking a bee's footpad is a concave hexagonal microcavity. Drainage grooves are provided between the multiple micron-sized columnar arrays.

[0010] Furthermore, the diameter of the conical microporous channel gradually decreases along the direction away from the adhesion interface; the inner wall of the conical microporous channel is provided with a multi-level microgroove structure that mimics the pitcher plant, for forming a primary capillary column.

[0011] Furthermore, the multi-level microgroove structure includes alternating small microgrooves and large microgrooves.

[0012] Furthermore, the biomimetic wet adhesion layer 1 is subjected to hydrophilic modification treatment.

[0013] Furthermore, the hydrophilic modification treatment is performed by oxygen plasma treatment followed by coating with a 1 wt% concentration of polyvinyl alcohol, thereby stabilizing the surface contact angle to below 15°.

[0014] Compared with the prior art, the beneficial effects of the present invention are:

[0015] 1) High reliability of biomimetic wet adhesion: Through multi-level biomimetic microstructure design, the morphology of the interface liquid film is dynamically controlled to achieve liquid bridge fragmentation and maximize the three-phase contact line. It can generate high-strength normal and shear adhesion forces in a humid environment, effectively preventing interface failure under moisture or dynamic load.

[0016] 2) High efficiency in liquid management: Through the synergistic effect of the conical microporous channel and the multi-level microgroove structure on the inner wall of the channel, a high-intensity Laplace pressure difference can be generated while reducing drag on the surface of the conical microporous channel, so as to realize the rapid directional transport of liquid, quickly discharge the interface liquid, avoid excessive liquid accumulation, and maintain the optimal hydration state of the interface.

[0017] 3) Decoupling and Synergy of Interface Stability and Permeability: The efficient liquid transport channel ensures high interface permeability (water vapor transmission rate is much higher than traditional sealing patches), avoiding interface bulging, detachment, and discomfort caused by liquid retention and vapor accumulation, making it suitable for long-term wear or operation. The "adhesion" and "transmission" functions are physically separated, and their synergistic enhancement is achieved through structural design, fundamentally resolving the inherent contradiction between wet adhesion and liquid management. Attached Figure Description

[0018] Figure 1 This is a first-view isometric view of the present invention;

[0019] Figure 2 This is a schematic diagram of the layered structure of the present invention;

[0020] Figure 3 This is a schematic diagram of the surface structure of the present invention;

[0021] Figure 4 This invention follows Figure 3 A schematic diagram of the middle AA line;

[0022] Figure 5 This is a schematic diagram of the first-level hexagonal micropillars on the surface of the biomimetic wet adhesion layer of the present invention. Figure 3 (Enlarged view of B in the image);

[0023] Figure 6 This is a schematic diagram of the second-level hexagonal concave cavity on the surface of the biomimetic wet adhesion layer of the present invention. Figure 5 (Enlarged view of C in the middle);

[0024] Figure 7 This is a schematic diagram of the composite pore formed by the conical microporous channel and the biomimetic wet adhesion layer through-hole of the present invention.

[0025] Numbering on the map:

[0026] 1-Bionic wet adhesion layer; 1.1-Through holes;

[0027] 2-Multi-level biomimetic microstructure array; 2.1-Concave cavity mimicking bee foot pads; 2.2-Hexagonal frame mimicking bee foot pads; 2.3-Drainage groove;

[0028] 3-Conical micropore channel; 3.1-Small microgroove; 3.2-Large microgroove;

[0029] 4-Sweat directional transport layer. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, it should be noted that these embodiments are not intended to limit the present invention. All equivalent changes or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are within the scope of protection of the present invention.

[0031] like Figures 1-7As shown, this embodiment provides a bionic composite patch for a wet surface, which is characterized in that it includes a bionic wet adhesion layer 1 and a sweat directional transport layer 4 arranged from top to bottom; the bionic wet adhesion layer 1 is a flexible film with a multi-level bionic (imitating the structures of tree frog and bee foot pads) microstructure array 2 on its surface, which is used to form a stable liquid bridge at the wet interface to provide strong wet adhesion force; the sweat directional transport layer 4 is provided with a plurality of conical microporous channels 3, which are used to generate a Laplace pressure difference to achieve rapid directional transport of liquid; the bionic wet adhesion layer 1 has through holes 1.1 in the gaps of the multi-level bionic microstructure array 2, and the conical microporous channels 3 correspond to the through holes 1.1 one by one to form composite holes; the bionic wet adhesion layer 1 and the sweat directional transport layer 4 are assembled into an integral structure through chemical bonding, which is used to jointly maintain the dynamic balance of the interfacial liquid through synergistic action. The bionic wet adhesion layer 1 and the sweat directional transport layer 4 are physically separated in space and cooperate functionally to jointly maintain the dynamic liquid balance of the adhesion interface.

[0032] In this embodiment, the bionic microstructure array 2 includes a plurality of micron-scale column arrays arranged in a hexagonal pattern. The micron-scale column array includes a hexagonal frame 2.2 imitating the bee foot pad and a nano-scale concave cavity 2.1 imitating the bee foot pad, and the concave cavity imitating the bee foot pad is a concave hexagonal microcavity; there are drainage grooves 2.3 between the plurality of micron-scale column arrays.

[0033] Refer to Figure 5 、 Figure 6 As shown, the parameters of the micron-scale column array are: the side length of the column L = 120 μm, the height of the microcolumn is 96 μm, and the column spacing W = 60 μm. The side length of the hexagonal concave cavity on the surface of the microcolumn l = 12 μm, the cavity spacing d = 8 μm, and the cavity depth is 2 μm.

[0034] In this embodiment, the aperture of the conical microporous channel 3 gradually decreases in the direction away from the adhesion interface; the inner wall of the conical microporous channel is provided with a multi-level microgroove structure imitating Nepenthes, including alternately arranged small microgrooves 3.1 and large microgrooves 3.2, which helps to form a primary capillary liquid column and helps a large amount of liquid in the center of the channel to spread upward rapidly. The channel is used to generate a Laplace pressure difference to drive the liquid to be transported away from the adhesion interface directionally. In this embodiment, the half cone angle of the conical microporous channel is 25°, the channel height is 0.8 - 1 mm, the inlet aperture is 1.6 mm, and the outlet aperture is​​​​​The fabrication process of this biomimetic composite patch includes the following steps:

[0037] (I) Mold Manufacturing

[0038] The biomimetic wet adhesion layer mold is prepared using microfabrication technology: microstructure patterns are formed on a silicon wafer through processes such as spin coating with SU-8 photoresist, soft baking, ultraviolet exposure, and development, and then transferred to a silicon substrate by reactive ion etching (RIE) to obtain a silicon-based mold with precise micropillar and cavity structures.

[0039] The sweat-directed transport layer mold is formed in one step using micro-nano scale 3D printing technology, resulting in a photosensitive resin mold with conical through holes and microgrooves on the inner wall.

[0040] (II) Molding

[0041] The obtained mold is subjected to vapor phase fluorination demolding treatment to form an anti-adhesion layer on its surface;

[0042] After mixing PDMS prepolymer and curing agent at a ratio of 10:1 and vacuum degassing, the mixture is spin-coated onto the surface of a biomimetic wet adhesive layer mold at 200-300 rpm for 60 seconds, with the thickness controlled at 0.4 mm. After curing in a 75°C oven for 2 hours, the mixture is demolded to obtain the biomimetic wet adhesive layer.

[0043] The same proportion of PDMS mixture was poured into the mold of the sweat-directed transport layer and a stepped curing process was adopted: first, preheat curing at 40℃ for 30 minutes, and then deep curing at 80℃ for 2 hours to ensure that the material is fully cross-linked and free of internal defects. After demolding, the sweat-directed transport layer is obtained.

[0044] (III) Hydrophilic treatment and bonding

[0045] After the two layers to be bonded are treated with oxygen plasma (power 50W, oxygen flow rate 50sccm, time 90 seconds), they are immediately aligned and bonded. A pressure of 0.1MPa is applied and held for 10 minutes. The chemical bonding characteristics of the PDMS surface active groups are used to achieve a strong bond, and finally the biomimetic composite film patch is obtained.

[0046] The present invention has the following technical effects:

[0047] 1) High reliability of wet adhesion: Through multi-level biomimetic microstructure design, the morphology of the interface liquid film is dynamically controlled to achieve liquid bridge fragmentation and maximize the three-phase contact line. It can generate high-strength normal and shear adhesion forces in a humid environment, effectively preventing interface failure under moisture or dynamic load.

[0048] 2) High efficiency in liquid management: Through the synergistic effect of the conical microporous channel and the multi-level microgroove structure on the inner wall of the channel, a high-intensity Laplace pressure difference can be generated while reducing drag on the surface of the conical microporous channel, so as to realize the rapid directional transport of liquid, quickly discharge the interface liquid, avoid excessive liquid accumulation, and maintain the optimal hydration state of the interface.

[0049] 3) Decoupling and Synergy of Interface Stability and Permeability: The efficient liquid transport channel ensures high interface permeability (water vapor transmission rate is much higher than traditional sealing patches), avoiding interface bulging, detachment, and discomfort caused by liquid retention and vapor accumulation, making it suitable for long-term wear or operation. The "adhesion" and "transmission" functions are physically separated, and their synergistic enhancement is achieved through structural design, fundamentally resolving the inherent contradiction between wet adhesion and liquid management.

[0050] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A biomimetic composite patch for damp surfaces, characterized in that, It includes a biomimetic wet adhesion layer (1) and a sweat directional transport layer (4) arranged from top to bottom; The biomimetic wet adhesion layer (1) is a flexible film with a multi-level biomimetic microstructure array (2) on its surface, which is used to form a stable liquid bridge at the wet interface to provide strong wet adhesion. The sweat directional transport layer (4) is provided with multiple conical microporous channels (3) to generate a Laplace pressure difference to achieve rapid directional transport of liquid; The biomimetic wet adhesion layer (1) has through holes (1.1) in the gaps of the multi-level biomimetic microstructure array (2), and the conical micropore channel (3) corresponds one-to-one with the through holes (1.1) to form a composite pore; the biomimetic wet adhesion layer (1) and the sweat directional transport layer (4) are bonded to form an integral structure, which is used to maintain the dynamic balance of the interface liquid through synergistic effect.

2. The biomimetic composite patch for damp surfaces according to claim 1, characterized in that, The biomimetic microstructure array (2) includes multiple micron-sized columnar arrays arranged in a hexagonal pattern. The micron-sized columnar array includes a hexagonal frame (2.2) that mimics the footpad of a bee and a nano-sized concave cavity (2.1) that mimics the footpad of a bee. The concave cavity (2.1) that mimics the footpad of a bee is a concave hexagonal microcavity. Drainage grooves (2.3) are provided between the multiple micron-sized columnar arrays.

3. The biomimetic composite patch for damp surfaces according to claim 1, characterized in that, The diameter of the conical microporous channel (3) gradually decreases along the direction away from the adhesion interface; the inner wall of the conical microporous channel is provided with a multi-level microgroove structure that imitates pitcher plants, which is used to form a primary capillary column.

4. The biomimetic composite patch for damp surfaces according to claim 3, characterized in that, The multi-level microgroove structure includes alternating small microgrooves (3.1) and large microgrooves (3.2).

5. The biomimetic composite patch for damp surfaces according to claim 1, characterized in that, The biomimetic wet adhesion layer (1) is hydrophilic modified.

6. The biomimetic composite patch for damp surfaces according to claim 5, characterized in that, The hydrophilic modification treatment is performed by oxygen plasma treatment followed by coating with a 1 wt% polyvinyl alcohol coating, which stabilizes the surface contact angle below 15°.

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