Submicron/nano-structured icephobic surfaces made from fluorinated polymethylsiloxane and octavinyl-POSS

Abstract

Fluorinated hybrid films composed of fluorinated polymethylsiloxane (PMHS–xFMA, x=6, 13, 17) and octavinyl-polyhedral oligomeric silsesquioxanes (OVPOSS) were prepared for icephobic applications. PMHS–xFMA with diverse fluorinated side groups were synthesized via hydrosilylation of polymethylhydrosiloxane (PMHS) with fluorinated methacrylate (xFMA), i.e., hexafluorobutyl methacrylate (6FMA), tridecafluorooctyl methacrylate (13FMA) and heptadecafluorodecyl methacrylate (17FMA), respectively. Characterizations of atomic force microscope and scanning electron microscope indicated that surfaces of the hybrid films consisted of submicron/nano-scaled OVPOSS aggregates, and the root-mean-square roughness (Sq) could vary from 42.6nm to 145.2nm with various OVPOSS content (5–20wt%). Wettability measurements of the prepared films demonstrated that the relatively longer fluorinated side groups in PMHS–17FMA were beneficial for decreasing surface energy and enhancing hydrophobic properties. However, the fluorinated hybrid films with PMHS–17FMA presented higher ice shear strengths due to the stronger interfacial interactions between the film surface and ice/water. The film prepared by PMHS–13FMA and 10wt% of OVPOSS with proper roughness (90.2nm) performed the lowest ice shear strength (188.2±13.4kPa) among all the samples. Dynamic water droplet impact measurement revealed that the rougher surface with the mass fraction of OVPOSS more than 10wt% and Sq larger than 90nm could repel water droplets. The submicron/nano-structured surface of PMHS–xFMA and OVPOSS was expected for anti-icing applications.