Preparation And Anti-icing Performance Of Environment-friendly Superhydrophobic Coatings

The formation of ice is a very common natural phenomenon,but the ice accumulation on surfaces has brought many problems to the industrial development and environmental governance of countries all over the world,and even leads to the loss of life and property.Superhydrophobic coatings have a great potential in anti-icing compared with conventional deicing methods such as salt sprinkling,hot melting,artificial deicing and vibration deicing.Superhydrophobic coatings can effectively delay the freezing time of water on the coating surface and reduce the adhesion of ice on the coating surface.However,the conventional superhydrophobic coatings have some problems,such as complex preparation method,high pollution,low stability and poor anti-icing performance.So,it is difficult to achieve ideal anti-icing effect.Therefore,how to use low-cost,non-toxic and harmless natural materials,and through a simple and effective method to build a highly efficient,stable and green superhydrophobic anti-icing coating has far-reaching significance.In this paper,based on the natural clay minerals,the green superhydrophobic coatings with stable and excellent anti-icing performance have been prepared,and the wetting mechanism and ice adhesion mechanism of the coatings were deeply studied.Firstly,hexadecyltrimethoxysilane(HDTMS)and tetraethylorthosilicate(TEOS)were hydrolyzed and condensed to the surface of diatomite(DE)particles for surface modification in an aqueous system,and then the uniform hexadecyl polysiloxane(HD-POS)modified DE particles(DE@HD-POS)suspension was prepared.The PU/DE@HD-POS superhydrophobic coatings were prepared by spray-coating sequentially the waterborne polyurethane(PU)solution and the as-prepared DE@HD-POS suspension onto various substrates with the PU coating as the adhesive layer.The coatings have excellent superhydrophobicity.The contact angle(CA)and sliding angle(SA)of the coatings are 168.1°and 4.9°,respectively.Under the condition of-15℃ and 60% relative humidity,the icing time of water droplets on different substrates is 315~516 s,and the ice adhesion is 68.8 k Pa~85.4 k Pa.Moreover,the coatings show excellent mechanical,chemical and environmental stability.The coatings are still superhydrophobic by water jetting at 50 k Pa for 30 min.The coatings can resist the erosion of different corrosive solutions and long-term ultraviolet radiation.In addition,by oxidizing pyrrole(PY)with ammonium persulfate(APS),polypyrrole(PPY)was formed and loaded on the surface of natural clay attapulgite(ATP)particles to obtain PPY/ATP particles with photothermal effect,and then the surface of PPY/ATP particles was modified by HDTMS and TEOS to obtain uniform PPY/ATP particles(PPY/ATP@HD-POS)suspension.By mixing the as-prepared PPY/ATP@HD-POS suspension with an appropriate amount of silicone resin,stable PPY/ATP@HD-POS photothermal superhydrophobic coatings were finally obtained via spraying coating.The coatings exhibit excellent superhydrophobic property and photothermal effect.The CA and SA of the coatings are 162.7° and 2.7°,respectively.Under 1 sun irradiation,the surface temperature of the coating can quickly rise to about 80℃ within 10 min.As a result,the coating has good anti-icing performance.In the outdoor environment,the freezing time of water droplets on the coating surface is significantly improved in the absence of light.Under sunlight irradiation,the ice and snow on the coating surface can melt rapidly.Moreover,the coatings show excellent mechanical,chemical and thermal stability.The coating is still superhydrophobic by water jetting at 50 k Pa for 30 min.The coating can resist the erosion of different corrosive solutions and the high temperature of 400 °C.This paper solves the bottlenecks that restrict the practical applications of superhydrophobic coatings.The green fluorine-free systems are used to prepare stable superhydrophobic and photothermal superhydrophobic coatings.The stability of the coatings has been studied in detail,and the application of the coatings in anti-icing has been explored.It provides a new idea for the preparation of environmentally friendly superhydrophobic coatings.