Effect of block sequence on responsive behavior of core-shell diblock polymer brushes

In this work, two kinds of core-shell diblock polymer brushes, i.e., poly(acrylic acid)-b-poly(N-isopropyla crylamide) and poly(N-isopropylacrylamide)-b-poly(acrylic acid) diblock polymer brushes with polystyrene cores (PSV@PAA-b-PNIPA and PSV@PNIPA-b-PAA), were prepared by surface-initiated photoinifer-termediated polymerization (SI-PIMP). Both of them are demonstrated to be dually responsive to pH and temperature. Compared to brushes with random polymer chains of PAA and PNIPA, the control of PAA and PNIPA block sequence not only affects the responsive behavior, but also changes the competition between intermolecular and intramolecular forces which results in remarkable conformation variation. The inverse temperature response of PSV@PAA-b-PNIPA could shine light on structure design of polymer brushes for applications such as protein separation. (C) 2018 Elsevier B.V. All rights reserved.