CN-121976399-A - Super-hydrophobic self-cleaning PTFE-based composite film and application and preparation method thereof

Abstract

The invention provides a super-hydrophobic self-cleaning PTFE-based composite membrane and an application and a preparation method thereof, comprising a PTFE fiber membrane, wherein the outer surface of the PTFE fiber membrane forms a super-hydrophobic fluorine enrichment layer, the inner surface of the PTFE fiber membrane forms a PTFE/silica gel three-dimensional mechanical interlocking structure layer and a porous silica gel layer, wherein the PTFE/silica gel three-dimensional mechanical interlocking structure layer is obtained by in-situ growth and solidification of liquid silica gel on the inner surface of the PTFE fiber membrane, and the porous silica gel layer is obtained by foaming the liquid silica gel by a heat-stable foaming agent, so that the effects of outer hydrophobicity, inner softness and interlayer firm adhesion are realized, and the super-hydrophobic, long-acting self-cleaning, mechanical durability, high touch fidelity and strong interface bonding characteristics can be achieved.

Inventors

• GUO YUHAI
• LI CHENGCAI
• LIU GUOJIN
• ZHU HAILIN
• ZHANG HUAPENG
• JIANG XUELIANG
• LI JIUMING

Assignees

• 浙江理工大学
• 浙江格尔泰斯环保特材科技股份有限公司
• 杭州晟聚环保科技有限公司

Dates

Publication Date

20260505

Application Date

20260408

Claims (10)

1. 1. The preparation method of the super-hydrophobic self-cleaning PTFE-based composite membrane is characterized by comprising the following steps of: s1, performing energy beam scanning irradiation and in-situ annealing treatment on the outer surface of a PTFE fiber membrane to form a superhydrophobic fluorine-enriched layer; s2, coating the coating liquid on the inner surface of the PTFE fiber membrane, and placing the coating liquid in a vacuum chamber for negative pressure treatment to obtain a composite PTFE membrane, wherein the coating liquid contains liquid silica gel and a thermal decomposition type chemical foaming agent; and S3, heating the composite PTFE film at a first temperature for 3-10 min, and then heating the composite PTFE film at a second temperature for 5-15 min to obtain the super-hydrophobic self-cleaning PTFE-based composite film, wherein the first temperature is 80-120 ℃, and the second temperature is 10-30 ℃ higher than the decomposition temperature of the thermal decomposition type chemical foaming agent.
2. 2. The method for preparing a super-hydrophobic self-cleaning PTFE based composite film according to claim 1, wherein the energy beam irradiation treatment and the annealing treatment are performed under an inert gas atmosphere.
3. 3. The method for preparing the super-hydrophobic self-cleaning PTFE-based composite film according to claim 1, wherein the energy beam is ArF excimer laser with the wavelength of 193nm, the energy density is 0.5-2.0J/cm < 2 >, the pulse width is 10-30 ns, and the scanning speed is 5-20 mm/s.
4. 4. The method for preparing the super-hydrophobic self-cleaning PTFE-based composite film according to claim 1, wherein the in-situ annealing condition is that the film is kept at a temperature of 250-280 ℃ for 30-60 seconds and then cooled.
5. 5. The method for preparing the super-hydrophobic self-cleaning PTFE-based composite membrane according to claim 1, wherein the thickness of the fluorine-enriched layer is 1-10 nm, the outer surface of the PTFE fiber membrane is a super-hydrophobic layer without coating dependence, and the contact angle of the super-hydrophobic layer is more than 155 degrees.
6. 6. The method for preparing the super-hydrophobic self-cleaning PTFE-based composite film according to claim 1, wherein the coating liquid is obtained by dissolving liquid silica gel and a thermal decomposition type chemical foaming agent in ethyl acetate.
7. 7. The preparation method of the super-hydrophobic self-cleaning PTFE-based composite membrane according to claim 1, wherein the liquid silica gel is one or a combination of Ecoflex 0030 type silica gel and liquid silica gel LSR-9650A/B type silica gel, and the thermal decomposition foaming agent is one or a combination of azodicarbonamide and azodicarbonamide potassium formate.
8. 8. The preparation method of the super-hydrophobic self-cleaning PTFE-based composite film according to claim 1, wherein the mass ratio of the liquid silica gel to the ethyl acetate is 1:1, and the addition amount of the thermal decomposition type foaming agent is 1-3% of the total weight of the liquid silica gel.
9. 9. The super-hydrophobic self-cleaning PTFE-based composite membrane is characterized by being prepared by a preparation method of the super-hydrophobic self-cleaning PTFE-based composite membrane according to any one of claims 1 to 8, and comprises a PTFE fiber membrane, wherein a super-hydrophobic fluorine enrichment layer is formed on the outer surface of the PTFE fiber membrane, a PTFE/silica gel three-dimensional mechanical interlocking structure layer and a porous silica gel layer are formed on the inner surface of the PTFE fiber membrane, the PTFE/silica gel three-dimensional mechanical interlocking structure layer is formed by in-situ growth and solidification of liquid silica gel on the inner surface of the PTFE fiber membrane, and the porous silica gel layer is obtained by foaming the liquid silica gel by a heat-stable foaming agent.
10. 10. Use of the superhydrophobic self-cleaning PTFE-based composite film according to claim 9 as a robotic skin scene.

Description

Super-hydrophobic self-cleaning PTFE-based composite film and application and preparation method thereof Technical Field The invention relates to the field of electronic skin, in particular to a super-hydrophobic self-cleaning PTFE (polytetrafluoroethylene) based composite film which can be used for robot electronic skin, in particular to the outermost layer of a robot dexterous hand, and an application and a preparation method thereof. Background Along with the deep penetration of the robot technology into complex unstructured environments such as medical operations, disaster relief, precise micro-assembly, home services and the like, the robot dexterous hand and the electronic skin at the tail end of the grasping hand are used as the touch perception core components, and face severe environmental interference challenges. Specifically, pollutants such as water, greasy dirt, blood, dust, biological dirt and the like are extremely easy to adhere to the electronic skin sensing surface, so that touch signal distortion and sensing sensitivity attenuation are caused, even short circuit and functional failure of the sensor are caused, and the operation stability and operation precision of the robot in a complex scene are seriously restricted. In order to solve the above protection problem, various electronic skin surface protection schemes have appeared in the prior art, but all have obvious technical limitations, and it is difficult to consider the comprehensive requirements of superhydrophobic protection, mechanical durability, tactile sensing fidelity and interface bonding stability, and specific defects are as follows: 1. The function sacrificial protection is realized by thickening the encapsulation layers such as silica gel, polyurethane and the like so as to improve the protection capability, but the thick encapsulation layer can greatly attenuate the perception sensitivity and resolution of the electronic skin to micro force and surface texture, lose the precise touch perception advantage of the robot dexterous hand and cannot meet the use requirements of scenes such as precise assembly, medical operation and the like. 2. The super-hydrophobic coating has insufficient durability, namely, surface protection is realized by adopting a spray coating mode, a plating perfluorinated silane mode and other super-hydrophobic coating modes, but the bonding force between the super-hydrophobic coating and a substrate is weak, the coating is easy to wear and fall off under the dynamic working conditions of repeated grasping, friction and bending of a robot smart hand, the super-hydrophobic effect is lost, the fallen coating particles also secondary pollution to a sensing part, the repairing difficulty of the coating is high, and long-acting protection cannot be realized. The PTFE material has poor integration suitability, namely a Polytetrafluoroethylene (PTFE) film becomes a potential preferable material for electronic skin protection due to excellent chemical inertness and basic hydrophobicity, but the original smooth surface of PTFE lacks a bionic micro-nano structure, has insufficient self-cleaning capability and super-hydrophobic performance and extremely low surface energy, and is difficult to form a firm and reliable bonding interface with a lower flexible sensor silica gel matrix, so that the problems of interface stripping and layering are easy to occur in the dynamic deformation and reciprocating motion of a robot smart hand, and the protection is invalid. 4. The design of the protective structure is simplified, the existing electronic skin hydrophobic protective layer is mostly made of homogeneous materials or is of a simple single-layer coating structure, the gradient and multifunctional structural design is lacked, the rejection capability to low-surface-tension liquids such as oils and the like is weak, the pressure adaptability is avoided, the hydrophobic performance is easy to quickly attenuate under the action of dynamic pressure of the robot gripping, and the problem of multiple pollution in complex scenes cannot be solved. In summary, developing a high-performance gradient composite protective film adapted to a robot smart hand becomes a key requirement for breaking through the bottleneck of the robot touch perception technology in a complex environment. Disclosure of Invention The invention aims to provide a super-hydrophobic self-cleaning PTFE-based composite film and a preparation method thereof, wherein the outer layer of the super-hydrophobic self-cleaning PTFE-based composite film is a PTFE fiber film with a fluorine-enriched layer formed by energy beam induced rearrangement on the surface, and the inner layer is a PTFE/silica gel three-dimensional mechanical interlocking structure layer which is in three-dimensional interlocking with the PTFE fiber film at an interface and a porous silica gel layer with a porous structure, so that the effects of outer hydrophobicity, inner softness and interla