Multi-component hierarchically structured polymer brushes

Abstract

Polymer brushes offer patternable, robust, two-dimensional coatings that can be used for, among other applications, the capture and release of medicine and nanoparticles. In this contribution, we demonstrate a technique for extending the patterning ability into the third dimension. This technique, which combines photolithography and ATRP, uses a photoresist to mask and expose chosen areas of a polymer brush. The polymer brush grows only in the exposed areas and subsequent masking and growth processes can be repeated owing to the living nature of ATRP, and thus allowing complex three-dimensional pattern formation. The concept is demonstrated by creating multi-component block-copolymer brush patterns of poly(2-hydroxyethyl methacrylate) (PHEMA), poly(N-isopropylacrylamide) (PNIPAM) and poly(glycidyl methacrylate) (PGMA). Colorimetric visualization of the swell–deswell transition of the partially hydrated and fully hydrated patterns confirm that PGMA patterned on top of PNIPAM alters swelling and the kinetics of the transition.