Synthesis and characterization of a poly(N-isopropylacrylamide) with β-cyclodextrin as pendant groups

A novel linear poly(N-isopropylacrylamide) (PNIPA) with beta-cylodextrin (beta-CD) moiety (PNIPA-beta-CD) was synthesized by the conjugation of beta-CD carrying amino groups (EDA-beta-CD) onto PNIPA with epoxy groups (P(NIPA-co-GMA), M-n = 3.86 X 10(4)), and the related reaction conditions are investigated. PNIPA-beta-CD was characterized by means of IR, NMR and UV spectroscopes, element analysis, and differential scanning calorimetry (DSC). The number-average molecular weight (M.) and the beta-CD content of the obtained PNIPA-beta-CD are 4.87 x 10(4) and 18.8 wt %, respectively. PNIPA-beta-CD can not only respond to temperature stimuli but also include guest molecules. Lower critical solution temperature (LCST) of aqueous PNIPA-beta-CD solution is similar to that of PNIPA. The association constant (K-a) for PNIPA-beta-CD with methyl orange (MO) is 2.4 x 10(3) L mol(-1) at pH 1.4, which is comparable to that of EDA-beta-CD (K-a = 2.9 x 10(3) L mol(-1)). (c) 2005 Wiley Periodicals, Inc.