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|Section3= }} Poly(''N''-isopropylacrylamide) (variously abbreviated PNIPA, PNIPAAm, NIPA, PNIPAA or PNIPAm) is a temperature-responsive polymer that was first synthesized in the 1950s.〔Schild, H. G. “Poly(N-isopropylacrylamide): experiment, theory and application” ''Progress in Polymer Science'', 1992, 17 (2), 163–249.〕 It can be synthesized from ''N''-isopropylacrylamide which is commercially available. It is synthesized via free radical polymerization and is readily functionalized making it useful in a variety of applications. It forms a three-dimensional hydrogel when cross-linked with ''N,N’''-methylene-bis-acrylamide (MBAm) or ''N,N’''-cystamine-bis-acrylamide (CBAm). When heated in water above , it undergoes a reversible lower critical solution temperature (LCST) phase transition from a swollen hydrated state to a shrunken dehydrated state, losing about 90% of its volume. Since PNIPA expels its liquid contents at a temperature near that of the human body, PNIPA has been investigated by many researchers for possible applications in tissue engineering and controlled drug delivery.〔Chung, J. E.; Yokoyama, M.; Yamato, M.; Aoyagi, T.; Sakurai, Y.; Okano, T. “Thermo-responsive drug delivery from polymeric micelles constructed using block copolymers of poly(N-isopropylacrylamide) and poly(butylmethacrylate)” Journal of Controlled Release, 1999, 62, 115–127. (Abstract )〕〔 Hu Yan and Kaoru Tsujii. “Potential application of poly(N-isopropylacrylamide) gel containing polymeric micelles to drug delivery systems” Colloids and Surfaces B: Biointerfaces. 2005, 46, 142–146. (Abstract )〕〔 Antunes F. , Gentile L. , Tavano L. , Oliviero Rossi C. , " Rheological characterization of the thermal gelation of poly(N-isopropylacrylamide) and poly(N-isopropylacrylamide)co-Acrylic Acid". Applied Rheology, 2009, Vol. 19, n. 4, pp. 42064-42069. (Abstract )〕 ==History== The synthesis of poly(N-isoproylacrylamide) first began with the synthesis of acrylamides monomer by Sprecht in 1956. In 1957, Shearer patented the first application for what would be later identified as PNIPA for the use as a rodent repellent. Early work was piqued by theoretical curiosity of the material properties of PNIPA. The first report of PNIPA came in 1968, which elucidated the unique thermal behavior in aqueous solutions. The 1980s marked an explosion in interest in PNIPAs with the realization of potential applications due to its unique thermal behavior in aqueous solutions.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Poly(N-isopropylacrylamide)」の詳細全文を読む スポンサード リンク
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