Nonbiofouling Coatings Using Bottlebrushes with Concentrated Polymer Brush Architecture
Chiaki Yoshikawa, Keita Sakakibara, Punnida Nonsuwan, Tomohiko Yamazaki, Yoshinobu Tsujii
Abstract
Concentrated polymer brushes (CPBs) are known to suppress biofouling phenomena, such as protein adsorption and cell adhesion. However, a cumbersome process is needed for their synthesis. Here, we report a simple and versatile method for fabricating nonbiofouling coatings that uses well-defined bottlebrushes instead of CPBs. First, a macroinitiator, poly[2-(2-bromoisobutyryloxy)ethyl methacrylate] (PBIEM), was synthesized by reversible addition-fragmentation chain transfer polymerization. Then, poly[poly(ethylene glycol) methyl ether methacrylate] was grafted from PBIEM through atom transfer radical polymerization to form well-defined bottlebrushes. By controlling the graft chain length, two types of bottlebrushes could be prepared, namely those with a semi-dilute polymer brush (SDPB) structure or a CPB structure on the surface of the outermost layer. Crosslinked films of the bottlebrushes were prepared on silicon wafers by spin-coating and subsequent radical coupling. Importantly, the CPB-type bottlebrush films showed significantly better nonbiofouling characteristics than those of the SDPB-type bottlebrush films.