Polymer brushes with phototriggered and phototunable swelling and pH response

Abstract

Photolabile polymer brushes with tailored length containing a photoremovable protecting group (NVOC) are prepared via the SI-ATRP method. Upon light irradiation, the NVOC group is removed to generate controlled densities of free amine groups (PAMA) randomly distributed along the brush. The presence of the ionizable groups induces a photo-triggered swelling response. The swelling degree can be tuned by the irradiation dose. A dual (light and pH), tunable response is demonstrated. A polymer brush with light- and pH-response is prepared from a methacrylate monomer with a 4,5-dimethoxy-2-nitrobenzyl (NVOC) photolabile NH 2 group. In the caged state, the polymer brush does not show a pH response. Controlled irradiation cleaves NVOC and turns on a dose-dependent pH response of a polycation brush. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.