Reversibly switchable double-responsive block copolymer brushes

Poly(2-hydroxyethyl methacrylate)-block-poly(N-isopropylacrylamide) (PHEMA-b-PNIPAM) was prepared by controlled surface -initiated ATRP from silicon substrates, and the resulting block copolymers were successfully converted into the corresponding PSEMA-b-PNIPAM by esterification of the hydroxy groups on the PHEMA block using excess of succinic anhydride. The PSEMA-b-PNIPAM block copolymer brushes respond to both temperature and pH stimuli. The double -responsive behavior of the block copolymer brushes in solution was investigated by height imaging and force-distance measurements of AFM. The results clearly show the responsive behavior of the smart block copolymer brushes.