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

Abstract

Abstract 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. Keywords: Surface-initiated ATRPpolyimidediblock copolymerprotein antifouling Notes a Reaction conditions: 100:1:0.2:1.5 [monomer]/[CuCl]/[CuCl2]/[Bpy] in water at room temperature. b Determined from the sensitivity factor-corrected XPS Cl 2p and C 1s core-level spectral area ratios. The [Cl]/[C] ratio for the initial PI-Cl surface is 1.7× 10−2. c Grafting yield is defined as (Wa-Wb)/SA, where Wa and Wb represent the weights of the dry membrane after and before grafting, respectively, and SA is the respective surface area of the membrane. d The static water contact angle of the pristine PI is about 65 circ . e Surface-initiated ATRP from the corresponding PI-P(PEGMA)2 surfaces.