Antifouling Surfaces Based on Fluorine-Containing Asymmetric Polymer Brushes: Effect of Chain Length of Fluorinated Side Chain.

The influence of chain length of a fluorinated side chain of an asymmetric polymer brush with poly(ethylene glycol) (PEG) side chains on the antifouling property was systematically investigated so as to obtain more knowledge for deepening our understanding of the structure-(antifouling)-property relationship of asymmetric polymer brush. A series of asymmetric polymer brushes, consisting of hydrophobic poly(pentafluoropropyl methacrylate) (PPTFMA) side chains with the number of repeat units of pentafluoropropyl methacrylate (PTFMA) ranging from 8 to 42 and hydrophilic PEG side chains, was first synthesized by sequential reversible addition-fragmentation chain transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP). Subsequently, thin films were prepared by spin-casting the solution of these brushes onto indium tin oxide (ITO) and SiO2 substrates. Water contact angle analysis showed that the hydrophobicity of the film surface increased with the length of PPTFMA side chain. The atomic force microscopy (AFM) measurement demonstrated that these films had a roughness of <3 and <10 nm onto ITO glass and SiO2 substrates, respectively. The antifouling behaviors of these films in bovine serum albumin (BSA) solution were evaluated by quartz crystal microbalance (QCM), which showed that the asymmetric brush surfaces had considerable antifouling performance with less protein adsorption in comparison with the bare surface. In addition, the films made from polymer brushes with shorter PPTFMA side chains exhibited better antifouling and fouling-release behaviors.