Spatiotemporal control over the host–guest characteristics of a stimulus-triggerable trifunctional polymer assembly

Abstract

The positional effect of stimuli-responsive units in tri-component copolymer vesicles is studied to explore variations in the host–guest properties of the assembly. We study this by placing pH-responsive diisopropylaminoethyl moieties in three distinct locations of a block copolymer assembly. In two of the three variations, these functionalities were randomly distributed in the hydrophobic or the hydrophilic domains of an amphiphilic diblock copolymer. In a third variation, this responsive functionality was incorporated as the middle block in a triblock copolymer. The results reveal that the solvent exposure of the responsive units holds the key for controlling the rate of molecular release from these polymer vesicles. The study also shows that equilibrium changes in the morphology of an assembly are not good indicators of the responsive host–guest properties of a polymer assembly.