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.

In this article, a simple synthesis method was applied to form a branch and tendril structure using hydroxyl-terminated silicone sol modified silica nanoparticles at high temperature, followed by mixing with fluoro-containing polyacrylate emulsion (PFA) to obtained a polydimethylsiloxane (PDMS)-SiO₂/PFA hybrid coating. The hydrophobic performance of the PDMS-SiO₂/PFA coating was further enhanced through the synergistic action of Si-O and F group. The obtained coating has a similar surface structure of lotus leaf and the contact angle can reach 142.2 ± 2.4°. The PDMS-SiO₂/PFA coating could delay the formation of frost crystal and the growth of frost layer. The defrosting droplets were difficult to adhere on the coating and could be easily rolled off for long frosting and defrosting cycles, which indicates the potential application of this coating in the field of frost suppression.