Surface-initiated Atom-transfer Radical Polymerization from Polyimide Films and Their Anti-fouling Properties

A simple one-step method for the chloromethylation of polyimide (PI) under mild conditions was used to introduce benzyl chloride groups into PI film surface. Covalently tethered hydrophilic polymer brushes of poly(ethylene glycol) monomethacrylate (PEGMA) and glycidyl methacrylate (GMA) were prepared via surface initiated atom-transfer radical polymerization (ATRP) from the chloromethylated PI surfaces using benzyl chloride groups as the active ATRP initiators. A kinetics study indicated that the chain growth from the films was in agreement with a controlled process. The dormant chain ends of the grafted polymer on the PI films could reinitiate the consecutive surface-initiated ATRP to prepare surface-functionalized diblock copolymer brushes on the PI films. The modified surface was characterized by X-ray photoelectron spectroscopy (XPS) after each modification stage. Protein adsorption experiments indicated that the PI-P(PEGMA) membrane exhibited substantially improved anti-fouling properties compared to the pristine PI surface.