Fabrication And Anti-icing/deicing Properties Of PDMS-matrix Composites With Microstructured Surfaces

The occurrence and accumulation of ice accretion and icing will cause high energy consumption or major hazards to transmission lines,insulators composite,power infrastructure and transportation systems in a low temperature and high humidity environment,which can cause serious safety problems.This article mainly focuses on improving the anti-icing ability of polydimethylsiloxane(PDMS)from two aspects of passive anti-icing and active deicing.In the passive anti-icing aspect,the direct template method is used to prepare microstructures on the sample surface.It can reduce the contact area between water droplets and the surface,thereby reducing the ice adhesion strength.In order to further enhance the anti-icing performance,a porous structure that can trigger multiscale crack is also introduced to further greatly reduce the ice adhesion strength.In the active deicing aspect,modified magnetic high-efficiency photothermal carbon nanotubes(CNTs)particles are added to the PDMS,which can migrate to the surface under a magnetic field.Thereby the light-to-heat conversion efficiency is improved.It can rapidly heating and deicing under the irradiation of near-infrared light.(1)In this paper,the traditional hydrothermal method was used to prepare Fe₃O₄nanoparticles.Highly cross-linked poly-(cyclotriphosphazene-co-4,4?-sulfonyldiphenol)(PZS)were used to directly coat Fe₃O₄nanoparticles.The obtained core-shell Fe₃O₄@PZS coated balls were loaded with CNTs to obtain magnetic fillers(CNTs/Fe₃O₄@PZS).The PDMS-matrix magnetic composite(PDMS/CNTs/Fe₃O₄@PZS)with an array microstructure on the surface was prepared by the direct template method and using hot embossing.The surfacecontactangle(CA)ofthetemplatecoatedwith trichloro(1H,1H,2H,2H-perfluorooctyl)silane(FDTS)is?152°,showing superhydrophobicity.After the droplet high-speed impact test,the surface can still maintain high hydrophobicity.The ice adhesion strength is?17k Pa,the freezing time is?11.5min,and the phase change time(liquid-Solid)?230s,the contact area between the surface and the droplets is relatively small,the frost growth is relatively neat and the distribution density is low in the ice adhesion test and the icing experiment test.Compared with flat PDMS,the ice adhesion strength is reduced by 30%,the freezing time is increased by 2.5 times,and the phase change process is increased by 95s and the frosting time is delayed by 6 minutes.In the photothermal effect test,the surface temperature of PDMS/CNTs/Fe₃O₄@PZS increases linearly with time and the internal magnetic filler,and the maximum can reach 250°C within20s.The efficiency of samples prepared under magnetic adsorption will increase by?40%.The temperature can reach a maximum of 280°C within 10s,and the entire frozen water droplet can be melted in only 20s.Even if the surface is damaged,the efficiency of the photothermal effect does not decrease.This combination of active deicing and passive anti-icing,as well as avoiding fatal defects of the coating and lubricating layer,are undoubtedly the characteristics for a new generation of anti-icing/deicing materials.(2)Three-dimensional flexible porous polydimethylsiloxane(p PDMS)materials are more widely used due to their relatively large specific surface area.A method for combining centrifuging and hot embossing was proposed for rapid mass production of highly interconnected p PDMS sandwich sponges with microstructure on top layer.As optimized sacrificial templates,the salts were rearranged in the PDMS by this method,and so the high connectivity facilitated salts dissolving in 3 h,which greatly improved the efficiency of the whole fabrication period.The weight ratio of PDMS to salt was 1.0 to 3.5,and the porosity can be kept at?70%.The combination of micron-scale truncated cones and highly interconnected pore structure endowed the sponge surface with a contact angle of up to?153°and ice adhesion strength as low as?6.78 k Pa,achieving ultra-low ice adhesion.In order to evaluate the influence of CNTs on the mechanical properties and photothermal effects of p PDMS/CNTs sponge,uniaxial tensile,compression tests,triboelectricity and photothermal deicing tests were carried out.For the PDMS/CNTs(7 wt%)sandwich sponge,the results show that the elongation at break is as high as?161%,the stress is as low as?23k Pa and the triboelectric voltage is 2.2V.Besides,its surface temperature rose rapidly from25°C to 100°C in 10 s through far-infrared light(808 nm)irradiation,and the ice droplets can be melted in 30s,achieving a remote deicing effect.The superhydrophobic and anti-icing/deicing sponges with high toughness property are expected to be used in multifunctional flexible electronic devices.