Effect of Fluorophilic- and Hydrophobic-Modified Polyglycerol-Based Coatings on the Wettability of Low Surface Energy Polymers

Abstract

Catechol-derived polymers form stable coatings on a wide range of materials including challenging to coat low surface energy polymers. Whether modification of the coating polymer with fluorophilic or hydrophobic groups is a successful approach to further favor the coating of hydrophobic or fluorophilic surfaces with catechol-based polymers remains ambiguous. Herein, we report the effect of a series of catechol-derived polyglycerol (PG)-based coatings and monolayer coatings on the wettability of polytetrafluoroethylene (PTFE), polystyrene, and poly(methyl methacrylate) surfaces. Coatings with a longer hydrophilic PG block resulted in surface coatings with water contact angles (WCAs) around 60° independently of the modification and substrate, while coatings with a longer hydrophobic anchoring block possessed more diverse WCAs up to (129 ± 10)°. Despite the generally small impact of the fluorophilic modification for most substrate/coating combinations, some fluorophilic modified coatings reduce the WCA of PTFE below Berg’s limit of 65°, indicating a shielding of fluorous segments from the surface.