Preparation and Anti-frost Performance of PDMS-SiO2/SS Superhydrophobic Coating

Abstract

Polydimethylsiloxane modified SiO2/organic silicon sol (PDMS-SiO2/SS) hybrid coating was synthesized via a simple two-step modification route. The nanoparticles (NPs) of PDMS-SiO2 were synthesized through a high temperature dehydration reaction by using silica and excessive PDMS. The NPs lapped with each other and formed a branch and tendril structure. Organic silicon sol (SS) added as basement introduced a hydrophobic group and protected the structure of the NPs. The PDMS-SiO2/SS hybrid coating exhibits a superhydrophobic performance with a maximum water contact angle of 152.82°. The frost test was carried out on a refrigerator evaporator, and the results showed that the coating did not merely delay the frost crystal time about 113 min but also increased the frost layer process time. Meanwhile, the defrosted water droplets rolled off from the coated surface easily which is a benefit for frost suppression performance of the next refrigeration cycle.