Agarose hydrogels embedded with pH-responsive diblock copolymer micelles for triggered release of substances.

Hybrid agarose hydrogels embedded with pH-responsive diblock copolymers micelles were developed to achieve functional hydrogels capable of stimulus-triggered drug release. Specifically, a well-defined poly(ethylene oxide) (PEO)-based diblock copolymer, PEO-b-poly(2-(N,N-diisopropylamino)ethyl methacrylate) (PEO(113)-b-PDPAEMA(31), where the subscripts represent the degrees of polymerization of two blocks), was synthesized by atom transfer radical polymerization. PDPAEMA is a pH-responsive polymer with a pKa value of 6.

Tuning of thermally induced sol-to-gel transitions of moderately concentrated aqueous solutions of doubly thermosensitive hydrophilic diblock copolymers poly(methoxytri(ethylene glycol) acrylate)-b-poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid).

We report in this article a method to tune the sol-to-gel transitions of moderately concentrated aqueous solutions of doubly thermosensitive hydrophilic diblock copolymers that consist of two blocks exhibiting distinct lower critical solution temperatures (LCSTs) in water. A small amount of weak acid groups is statistically incorporated into the lower LCST block so that its LCST can be tuned by varying solution pH. Well-defined diblock copolymers, poly(methoxytri(ethylene glycol) acrylate)-b-poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid) (PTEGMA-b-P(DEGEA-co-AA)), were prepared by reversible addition-fragmentation chain transfer polymerization and postpolymerization modification.

Rheological properties of aqueous micellar gels of a thermo- and pH-sensitive ABA triblock copolymer.

This article presents a systematic study of the effect of pH on the rheological properties of aqueous micellar gels formed from 10.0 wt % aqueous solutions of a thermo- and pH-sensitive ABA triblock copolymer, poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid)-b-poly(ethylene oxide)-b-poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid) (P(DEGEA-co-AA)-b-PEO-b-P(DEGEA-co-AA)). The block copolymer was synthesized by atom transfer radical polymerization of DEGEA and tert-butyl acrylate with a molar ratio of 100:5 from a difunctional PEO macroinitiator and subsequent removal of tert-butyl groups using trifluoroacetic acid.