Effect of sequence structure on wetting behaviors of fluorinated methacrylate polymers based on perfluorohexylethyl methacrylate and stearyl acrylate

Abstract

Due to the non-crystalline properties of short chain perfluoroalkyl groups, using short chain perfluoroalkyl to stabilize low surface free energy polymers has been a challenging task. In this study, we prepare a series of random copolymers poly(perfluorohexylethyl methacrylate)-co-poly(stearyl acrylate) (P13FMA-co-PSA) and block copolymers poly(perfluorohexylethyl methacrylate)-b-poly(stearyl acrylate) (P13FMA-b-PSA), and systematically investigate the effects of the sequence structure and the content of 13FMA of the fluorinated copolymers on surface free energy and surface reorganization. Static/dynamic contact angle goniometry and water/oil repellency analyses demonstrate that the random polymer P13FMA-co-PSA could not achieve low surface free energy and low surface reorganization at the same time. In contrast, for the block copolymer P13FMA-b-PSA, both low surface free energy and low surface reorganization are acquired simultaneously. The results of X-ray photoelectron spectroscopy (XPS), dynamic contact angle goniometry and differential scanning calorimetry (DSC) reveal the above-mentioned properties. The consecutive 13FMA segments improve the surface fluorine density, while the consecutive SA chains enhance the crystallinity of the SA segments, and further hinder the surface reorganization of the perfluoroalkyl groups. Therefore, P13FMA-b-PSA exhibits a higher utilization efficiency of fluorine atoms and a better structural stability than P13FMA-co-PSA.