Dual redox and thermoresponsive double hydrophilic block copolymers with tunable thermoresponsive properties and self-assembly behavior.

ABSTRACT

The synthesis, tunable thermoresponsive properties, and self-assembly of dual redox and thermoresponsive double hydrophilic block copolymers having pendant disulfide linkages (DHBCss) are reported. Well-defined DHBCss composed of a hydrophilic poly(ethylene oxide) block and a dual thermo- and reduction-responsive random copolymer block containing pendant disulfide linkages are synthesized by atom transfer radical polymerization. Their lower critical solution temperature (LCST) transitions are adjusted through modulating pendant hydrophobic-hydrophilic balance with disulfide-thiol-sulfide chemistry. Further, these DHBCss derivatives are converted to disulfide-crosslinked nanogels at temperatures above LCST through temperature-driven self-assembly and in situ disulfide crosslinking. They exhibit enhanced colloidal stability and further reduction-responsive degradability, thus demonstrating versatility of dual thermo- and reduction-responsive smart materials.