The Micro-nano Structure Design Of Novel Superhydrophobic Coatings And Their Anti-icing&Icephobic Propertics

Ice adhesion and accretion on the facilities of aviation, telecommunication, electricity and transportation can lead to major inconvenience for our daily life and even can cause great economic losses. Therefore, it is worthwhile to study anti-icing and icephobic coatings. It focuses on mitigating or even eliminating ice accumulation by extending freezing time and reducing ice adhesion strength. Extending freezing time is conducive to condensed water rolling off the substrates before it freezes via outside power, such as gravity, wind power and centrifugal forces. Reducing ice adhesion strength makes de-icing procedure facile even if the condensed water has frozen on the substrates. It has been proved that by optimizing surface physicochemical properties and surface topography, both ideal effects, anti-icing and icephobic, can be achieved simultaneously.Since the discovery of "Lotus effect", superhydrophobic surfaces have been applied in various fields because of self-cleaning behavior. It was found that super hydrophobic surfaces exhibited excellent anti-icing and icephobic property. Large static contact angle and small contact angle hysteresis facilitate the movement of water droplet and the air trapped in hierarchical structure help delay the freezing time as a thermal insulator. In the meantime, the well-defined superhydrophobic surface can influence the process of crystallization by decreasing the crystallization point, delaying the freezing time and changing the crystal form. Even ice formed on the substrates, it can reduce the adhesion between ice and substrate making de-icing process facile.Based on the analysis above, we synthesized two systems of anti-icing&icephobic superhydrophobic coatings by designing different micro-nano structures of superhydrophobic surface. We studied their superhydrophobic properties by the characterization of XPS,1H-NMR, SEM, TEM, AFM and static water contact angle. We also investigated the anti-icing&icephobic properties by the characterization of dynamic contact angle, DSC, static contact angle in the sub-zero environment and centrifugal forces. For the coating of fluoroalkyl acrylate copolymers filled with PTFE particles, we concluded that(1) The coating formed by mixing30%(wt) PTFE particles with fluoroalkyl acrylate copolymers exhibited superhydrophobility for its large static contact angle (155.2°) and small contact angle hysteresis(14.6°).(2) The results showed that the coating can facilitate the movement of water and reduce the crystallization point of water droplet by6.26’C, what’s more, the water droplet on-18℃surface would not freeze until1467s. Even if the ice is formed, the adhesion strength took up only5.35%of the one on uncoated glass. Therefore, The coating formed by mixing30%(wt) PTFE particles with fluoroalkyl acrylate copolymers exhibited anti-icing&icephobic properties.(3) Compared with the data reported by previous papers, the delayed freezing time was one of the middle ranked location. So, the anti-icing&icephobic property is not ideal.For the coating of grafting fluorinated random copolymers P(BA-co-EFOA) to SiO2nanoparticles, we concluded that(1) The hybrid material obtained by grafting fluorinated random copolymers to SiO2nanoparticles via surface initiate ATRP conceived fascinating properties such as controlled molecular structure and weight and good processability for the organic parts and high modulus, wonderful thermal and mechanical stability for the inorganic parts.(2) The coating formed by grafting fluorinated random copolymers to SiO2nanoparticles exhibited superhydrophobility for its large static contact angle (170.3°) and small contact angle hysteresis(2.7°).(3) The results showed that the coating can facilitate the movement of water and reduce the crystallization point of water droplet by6.82℃,what’s more, the water droplet on-18℃surface would not freeze until10054s. It is reasonable to conclude that the obtained superhydrophobic surface can prevent the formation of ice thoroughly with the help of outside forces.(4) Compared with the data reported by previous papers, the delayed freezing time was the longest one. So, the anti-icing&icephobic property is extremely excellent.