Blocklike Fluorocarbon and Hydrocarbon Copolymer Films via Surface-Initiated ATRP and Postpolymerization Reactions

We report a new method to prepare ultrathin blocklike copolymer films on metal surfaces with molecularly optimized surface and barrier properties. Copolymer films containing various fluorocarbon and/or hydrocarbon side chains were created by a one-step surface-initiated polymerization of poly(hydroxyethyl methacrylate) (PHEMA) followed by straightforward derivatization steps. Exposure of PHEMA to perfluorobenzoyl chloride results in a perfluoroaryl-modified PHEMA film that exhibits high conversion and outstanding barrier properties but does not present an oleophobic surface. We have previously demonstrated that fluorinated esters created in this manner may be hydrolyzed back to PHEMA by brief exposure to base. Controlled hydrolysis results in regeneration of PHEMA in the outer surface region that can be subsequently rederivatized with alkyl or fluoroalkyl acid chlorides to create copolymer films with tailored surface composition. Surface properties are solely affected by the species used during rederivatization while barrier properties result from the combined conversion, structuring, and surface properties of the copolymer film.