Dual Responsive Regulation of Host–Guest Complexation in Aqueous Media to Control Partial Release of the Host

Graphical Abstract

Control over host concentration: A colored DNP/Blue Box synthetic PNIPAm-co-PAA polymeric system featuring both thermo- and pH responsiveness allows the host concentration in aqueous media to be tuned in an orchestrated manner by controlling the partial collapse of the dual stimuli-responsive copolymer. This supramolecular polymeric system thus shows great potential for application in both T and pH chromic materials and for the development of more complex systems with molecular communication.

Abstract

The regulation of the concentration of a wide range of small molecules is ubiquitous in biological systems because it enables them to adapt to the continuous changes in the environmental conditions. Herein, we report an aqueous synthetic system that provides an orchestrated, temperature and pH controlled regulation of the complexation between the cyclobis(paraquat-p-phenylene) host (BBox) and a 1,5-dialkyloxynaphthalene (DNP) guest attached to a well-defined dual responsive copolymer composed of N-isopropylacrylamide as thermoresponsive monomer and acrylic acid as pH-responsive monomer. Controlled, partial release of the BBox, enabling control over its concentration, is based on the tunable partial collapse of the copolymer. This colored supramolecular assembly is one of the first synthetic systems providing control over the concentration of a small molecule, providing great potential as both T and pH chromic materials and as a basis to develop more complex systems with molecular communication.