Synthesis and Property of Temperature-Responsive Hydrogel with Movable Cross-linking Points

Kazuhiro Ishida, Takahiro Uno, Takahito Itoh, and Masataka Kubo

http://pubs.acs.org/doi/full/10.1021/ma301065j

The authors prepared a mechanically cross-linked gel using a cyclic PEG macromer co polymerized with NIPAAm. The pNIPAAm chain sections can thread through the PEG cycles, creating movable physical cross-links. Gels were characterized by swelling kinetics and compared to gels made of a linear PEG macromer copolymerized with pNIPAAm using bisacrylamide as a chemical crosslinker. The cycle-containing gels showed significantly higher swelling compared to gels containing the same amount of PEG in linear form. The authors attribute this to the movable nature of the threaded cross-links.