title: Stimuli-responsive coacervate induced in binary functionalized poly(N-isopropylacrylamide) aqueous system and novel method for preparing semi-ipn microgel using the coacervate.
abstract: We describe a novel method for preparing a stimuli-responsive semi-interpenetrating polymer network (semi-IPN) hydrogel microsphere using a thermoresponsive-type coacervation. The coacervate droplets were formed in the two-component nonionic poly(N-isopropylacrylamide-co-2-hydroxyisopropylacrylamide) (poly(NIPAAm-co-HIPAAm)) and ionic poly(NIPAAm-co-2-carboxyisopropylacrylamide) (poly(NIPAAm-co-CIPAAm)) aqueous system by heating the solution above the lower critical solution temperature. The resulting coacervate droplets included both kinds of polymer chains. Divinyl sulfone, which cross-links the hydroxyl groups of the poly(NIPAAm-co-HIPAAm), was added to the coacervate droplets. In this way, the stimuli-responsive semi-IPN hydrogel microsphere consisting of the poly(NIPAAm-co-HIPAAm) gel matrix and the linear poly(NIPAAm-co-CIPAAm) chains could be prepared, and their sizes were relatively homogeneous. That is, by utilizing the thermoresponsive coacervate droplets induced in the binary system, we could successfully prepare the fine stimuli-responsive semi-IPN hydrogel microsphere and it was prepared in a simple and easy method without any additives.
authors.affiliation: Department of Nanostructure and Advanced Materials, Graduate School of Science and Engineering, Kagoshima University, 1-21-40, Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Maeda
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Akasaki
authors.forename: Kazuya
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Takao
authors.initials: T
authors.lastname: Aoyagi
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000180:Acrylic Resins; D003432:Cross-Linking Reagents / Q000737:chemistry; D005782:Gels / Q000737:chemistry*; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; D003432:Cross-Linking Reagents; D005782:Gels; D011108:Polymers; D014867:Water; C052970:poly-N-isopropylacrylamide