title: Thermosensitivity of optically active hydrogels constructed with N-(L)-(1-hydroxymethyl)propylmethacrylamide.
abstract: We previously reported on the water soluble, optically active polymer, poly[N-(L)-(1-hydroxymethyl)propylmethacrylamide] (P(L-HMPMA)), which has lower critical solution temperatures of approximately 30 and 21 degrees C upon heating and cooling, respectively. The phase separation behavior of the P(L-HMPMA)-water binary system has a reversible and clear hysteresis during heating and cooling cycles. The present study describes the thermosensitive properties of the optically active polymer and its hydrogel. Circular dichroism and microcalorimetric measurements of the polymer in water supported the hypothesis that the soluble polymer chains might be compactly folded with an interaction between optically active side chains. In addition, these measurements showed the polymer chains in a state of relatively low hydration compared to that of P(D,L-HMPMA), which was free-radically synthesized from racemates of monomers. The solution properties reflected the swollen-shrunken behavior of corresponding hydrogels in response to temperature changes. The microscopic observation of aqueous polymer solutions and hydrogels also confirmed that the optically active properties of polymer chains affect their structure and thermosensitivity. SEM micrograph of the surfaces of the crosslinked P(L-HMPMA).
authors.affiliation: Department of Polymer Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo, Kyoto 606-8585, Japan. t-aoki@kit.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Aoki
authors.forename: Mika
authors.initials: M
authors.lastname: Muramatsu
authors.forename: Akino
authors.initials: A
authors.lastname: Nishina
authors.forename: Kohei
authors.initials: K
authors.lastname: Sanui
authors.forename: Naoya
authors.initials: N
authors.lastname: Ogata
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D002151:Calorimetry; D002942:Circular Dichroism; D003432:Cross-Linking Reagents / Q000494:pharmacology; D006358:Hot Temperature; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry*; D008689:Methacrylates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008858:Microscopy, Phase-Contrast; D008956:Models, Chemical; D011108:Polymers / Q000737:chemistry*; D011489:Protein Denaturation; D013696:Temperature; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; D003432:Cross-Linking Reagents; D020100:Hydrogels; D008689:Methacrylates; D011108:Polymers; C499796:poly(N-(1-hydroxymethyl)propylmethacrylamide); C052970:poly-N-isopropylacrylamide; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate