Versatile inhibition of marine organism settlement by zwitterionic polymer brushes

The anti-fouling character of polymer brushes against marine organisms was investigated by performing settlement tests with barnacle cypris larvae and mussel larvae in their adhesion period, as well as a marine bacteria colonization test. The settlement behavior of the marine organisms was carefully observed during the assays to obtain insight into the anti-fouling character. Zwitterionic poly(phosphobetaine) brushes and poly(sulfobetaine) brushes exhibited excellent anti-fouling characteristics for both macro-and micro-organisms, whereas poly(quaternary ammonium cation) brushes allowed mussel larvae settlement and bacteria adhesion. Regardless of the surface free energy and chain mobility, all of the hydrophobic polymer brushes showed poor anti-fouling character for the marine organisms tested. The surface charge and hydration state in saline seawater appear to be important factors in the versatile anti-fouling performance of zwitterionic polyelectrolyte brushes.