Abstract
We present a general approach for using surface-grafted stimuli-responsive diblock copolymer brushes as stimuli-sensitive and controllable release systems. Surface-initiated ATRP was used to grow sequentially a first block serving as an inner reservoir for loading and a second block that acts as a stimuli-responsive outer layer controlling the closure or opening of the brush in water. We show that the release kinetics of loaded model dyes (hydrophobic or hydrophilic) could be controlled by the second block switchable between the collapsed and extended brush chain states in response to temperature or pH change or exposure to light. On the one hand, diblock copolymer brushes of polystyrene-b-poly(N-isopropylacrylamide) (PS-b-PNIPAM) and poly(N,N′-dimethylacrylamide)-b-poly(N-isopropylacrylamide) (PDMA-b-PNIPAM) were synthesized to demonstrate the thermosensitive release of dyes based on the LCST-determined solubility switching between swollen and collapsed PNIPAM chains. On the other hand, a diblock copolym...
Published Version
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