화학공학소재연구정보센터
Polymer, Vol.126, 386-394, 2017
Doubly-crosslinked, emulsion-templated hydrogels through reversible metal coordination
Double crosslinking can be used to significantly improve the mechanical properties of gels. Here, doubly-crosslinked hydrogel polyHIPEs (DC-PHs), which exhibited rapid water absorption, enhanced mechanical properties, and shape memory behaviour, were generated by forming metal coordination crosslinks within covalently crosslinked hydrogel polyHIPEs (HG-PHs), hydrogels formed by templating within oil in-water high internal phase emulsions (HIPEs). The HG-PHs were based on acrylamide (AAm) and sodium acrylate (NaA), which provided -COO- groups, and were covalently crosslinked with N,N'-methylenebisacrylamide. The metal coordination crosslinking between the -COO- groups and Fe3+ was generated by adding FeCl3 to the HG-PHs. The interconnected macroporous structures and the rapid water absorption of the HG-PHs were preserved in the DC-PHs, while the mechanical properties, in both the swollen and dry states, were significantly enhanced. The metal coordination crosslinking was easily removed through the light-induced reduction of the Feat in the presence of citric acid. The reversibility of the metal coordination crosslinking endowed the DC-PHs with a multiple-cycle shape memory behaviour. (C) 2017 Elsevier Ltd. All rights reserved.