Hierarchical surface structure and performance of fluorinated copolymer films derived from side chain structure and α-position substitution of fluorinated monomeric units

Abstract

Low surface energy and low surface reconfiguration are two key properties being sought for fluorinated polymer films with short perfluoroalkyl groups, which are mainly determined by the molecular structure of fluorinated monomers. In this work, six typical C6 fluorinated monomers were selected to synthesize fluorinated polymer nanoparticles (f-PNPs) through miniemulsion polymerization. Fluorinated polymer films were further fabricated through spin-coating by using f-PNPs as the building blocks. Influences of the molecular structure of fluorinated monomers and heat treatment conditions on the surface element composition, arrangement of fluorinated side chains, surface morphology, surface performance, and underwater surface configuration of fluorinated polymer films were systematically investigated. The results showed both the fluorinated side chain structure and α-position substitution of fluorinated monomeric units played a significant role in the surface F enrichment extent, organized arrangement of fluorinated side chains at the surface, surface morphology, and finally the surface free energy. Generally, fluorinated polymer films with linear fluorinated side chains ended with –CF3 displayed stable low surface energy and low surface reorganization attributed to forming relatively organized packing structures of fluorinated side chains. This study contributes to providing a guide to design and fabricating low surface free energy nanomaterials or films with perfluoroalkyl (meth)acrylate copolymers bearing short perfluoroalkyl groups.