Understanding the Oxidative Stability of Antifouling\nPolymer Brushes

Abstract

Poly­(oligoethylene\nglycol methacrylate) (POEGMA) and zwitterionic\npolymer brushes have been widely used for constructing biocompatible\nor antifouling surfaces, and their oxidative stability is very important\nto the practical application. Herein, POEGMA, poly­(sulfobetaine methacrylate)\n(PSBMA), poly­(2-(methacryloyloxy)­ethyl phosphorylcholine) (PMPC),\nand poly­(carboxybetaine methacrylate) (PCBMA) were grafted on quartz\ncrystal microbalance (QCM) chips via surface-initiated atom transfer\nradical polymerization (SI-ATRP). XPS and MS analyses demonstrate\nthat the mass loss of these polymer brushes in oxidative environment\nis due to the scission of the polymer-anchoring segments. Molecular\nsimulation further illustrates this mass loss mechanism should be\nalways true for those polymer brushes anchored on different substrates.\nIn situ QCM monitoring indicates that, compared with zwitterionic\npolymethacrylates, POEGMA brushes show the lowest mass loss rate mainly\ndue to their cross-linked structures. This study sheds light on the\ncontradictory reports about the oxidative stability of POEGMA and\nzwitterionic polymethacrylate brushes up to now, and highlights the\nimportant role of the polymer-anchoring segments playing in the oxidative\nstability of polymer brushes.