Design And Fabrication Of Bio-inspired Superwetting Surface And Its Application In Anti-icing

After billions of years of continuous evolution,many natural creatures have demonstrated nearly perfect micro-nano structures to adapt to the laws of nature.For instance,the surfaces of many organisms exhibit special wetting behavior.Learning from nature,researchers gradually revealed the mechanism of superwetting surfaces through the study of special wetting behavior.Superwetting is a special wetting phenomenon between three phases(liquid,gas,and solid),and it is an extreme state of wettability.Super-wetting surface represented by superhydrophobic surface has been a wide concern in the past decades,and superwetting system has gradually also been improved.With the development of micro-nano manufacturing technology and bionics,a variety of superwetting surfaces have been developed,which cover many cross-cutting fields such as aerospace,energy,materials,information,and surface engineering,and have broad application prospects in oil-water separation,anti-icing,drag reduction,anti-fouling,anti-bacterial and biomedical fields.Currently,superwetting surface has been well-developed in the field of anti-icing with its special surface structure and chemical components,which not only enable droplets to leave the surface before nucleation and delay the nucleation and icing time but also reduce the ice adhesion force between ice and substrate so that ice can easily fall off the surface.Compared with traditional anti-icing methods,it shows the advantages of low energy consumption,high efficiency,and environmental protection.Therefore,it shows an important research value and significance in anti-icing applications.Although the superwetting surface that meets diversified needs has been gradually developed,it still faces some problems,and its industrial application is limited.1.The mechanical stability of superwetting surfaces,especially superhydrophobic surfaces,is not strong.This drawback seriously limits the practical application of superwetting surfaces.Therefore,how to fabricate superhydrophobic surfaces with wear resistance is the primary challenge that we need to focus on and solve.2.Although the responsive slippery surface can achieve switching wettability in the stimulated state,flexible control of anisotropic manipulation has been difficult to achieve.Most traditional slippery surfaces can only guide droplets to move in a specified path through light.3.Combining superwetting surfaces with active de-icing technology is the optimal strategy for antiicing,but the current combined active de-icing technology is single,and each active deicing method has its own shortcomings and strengths,so how to integrate various methods flexibly to form complementary advantages is lacking in the current research.In addition,active de-icing technology is facing the problem that only by completely melting the frozen ice or interface ice can the surface ice be driven away,which is inefficient.Therefore,we start from the design and fabrication of superwetting surface structures to address the above-mentioned problems that limit the development of superwetting surfaces in many aspects and initially explore their applications in the field of anti-icing.The main results are as follows.1.Preparation of wear-resistant superhydrophobic surface and its anti-icing performance.We propose a strategy to complement the advantages of rigid metal foam and superhydrophobic nanoporous polymers to design a wear-resistant superhydrophobic composite surface with a self-similar structure and verify its ability to resist external physical damage using diverse wear tests.The ability to resist external physical damage was verified using diverse wear tests.The wear-resistant superhydrophobic surface has excellent passive anti-icing properties,effectively extending the icing time by a factor of 11.The surface has good icephobic properties,with ice adhesion as low as about 3.3k Pa.In response to the problem of excessive loading voltage of current active electrothermal anti-icing surfaces,an active anti-icing surface with low voltage loading,programmable conductive paths,and tunable and predictable surface Joule heating was realized with the help of good electrical conductivity of metal foam.In addition,the surface is capable of patterned design as well as a high degree of co-integration,and its feasibility in real outdoor scenarios is verified.2.Preparation of anisotropic photothermal slippery surface and its applications.A study was conducted on the manipulation of droplet anisotropy on slippery surfaces,and a photothermally responsive slippery surface capable of anisotropic droplet manipulation was successfully fabricated.Further,using paraffin,a thermal phase change material,as a low surface energy lubricating fluid,the lubricating surface was switched from a gas/liquid/solid system(ALS)of solid paraffin to a gas/liquid/lubricant/solid system(ALLS)of a less frictional liquid paraffin surface by photo-thermal tuning of the paraffin phase change.The lubricated surface demonstrates tuning of light-responsive wettability and successfully achieves remote light-controlled actuation of various types of liquid droplets.The self-healing capability of the lubricated surface assisted by the light source was utilized to achieve the repair of external physical scratches.Finally,excellent anti-frosting and de-icing capability under light illumination was successfully demonstrated,and the application of contactless light-driven automatic feeding for acid and alkaline droplet detection was extended.This research provides new insights into the rational design of photo-thermally responsive slippery surfaces for applications in various tip orientations.3.Preparation of stretchable superhydrophobic films and study of photo/electric/stress synergistic anti-icing performance.To address the difficulty of maintaining superhydrophobicity under tensile deformation that exists in conventional stretchable superhydrophobic surfaces,a stretchable superhydrophobic surface with a multistage micro-nano structure was prepared by pre-stretching an elastic substrate.This multilevel micro-nano structure is formed by the combination of a micron-level fold structure triggered by strain recovery and superhydrophobic particles.The surface exhibits excellent mechanical stability under high tensile rates(200%),multiple cycles of stretching(500 cycles),twisting and bending,as well as UV resistance,high-temperature resistance,and chemical stability.In addition,to address the problems of single active deicing technology and low de-icing efficiency of current superhydrophobic surfaces for anti-icing applications,a light/electricity/stress synergistic anti-icing surface based on stretchable films was prepared using a pre-stretching method.The introduction of solar energy and electrical energy enables the pre-regulation of interfacial ice adhesion,and then the tensile force of the stretchable film enables the bypassing of the complete ice melting phase of the interface to achieve flexible,fast,and low-energy de-icing.This stretchable superhydrophobic film can be used in some mechanical bearing connections(e.g.,robotic arms,manipulators,etc.),which not only meets the stretching requirements but also provides superhydrophobic and anti-icing functions.