화학공학소재연구정보센터
Macromolecules, Vol.37, No.25, 9620-9625, 2004
Controlling PVA hydrogels with gamma-cyclodextrin
We report on the preparation and characterization of poly(vinyl alcohol) (PVA) hydrogels formed during freeze-thaw (F-T) cycles of their aqueous solutions containing gamma-cyclodextrin (gamma-CD). Crystalline inclusion compound (IC) formation was observed between PVA and gamma-CD in these gels at low concentrations of gamma-CD (gamma-CD:PVA molar ratios < 1:25). Confirmation of the existence of the channel structure for gamma-CD was achieved by characterizing the dried PVA/gamma-CD hydrogels with solid-state DSC, TGA, WAXD, and C-13 NMR. Some aspects regarding the mechanism and structure of PVA gels obtained via F-T cycles in the presence/absence of gamma-CD are presented based on UV-vis, swelling, solution H-1 NMR, and rheological observations. It was observed that the swelling and rheological responses of the aqueous PVA gels formed during F-T cycles in the presence of gamma-CD can be controlled by adjustment of the PVA:gamma-CD molar ratio employed during their gelation.