Access to Fluorinated Polymer Surfaces with Outstanding Mechanical Property, High Optical Transparency, and Low Surface Energy via Nonafluoro-tert-Butyl Group Introduction

Poly(methyl methacrylate-co-2-hydroxyethyl methacrylate) was fluorinated using nonafluoro-tert-butanol (pK(a) = 5.2), and the content of incorporated nonafluoro-tert-butyl (NFtB) groups was controlled by adjustment of the monomer ratio. The developed technique was very efficient, achieving an almost quantitative (>98%) conversion of polymer hydroxyl groups under mild reaction conditions. Quantum chemical calculations showed that the dipole moment of the methyl methacrylate unit (1.77 D) increased to 3.21 D upon NFtB group attachment, which indicated a concomitant polarity increase. The surface composition, intermolecular distances, and mechanical properties of polymer films were profoundly affected by fluorination, i.e., fluorinated polymer films exhibited outstanding mechanical property (indentation modulus approximate to 7.3 GPa), high optical transparency (similar to 96% for a glass slide coated on both sides), and low surface energy (similar to 14 mN m(-1)) while preserving the original solubility in common solvents.