Synthesis and properties of poly(N-isopropylacrylamide)/β-cyclodextrin ionic polymer

A poly(N-isopropylacrylamide)/beta-Cyclodextrin (PNIPAM/beta-CD) ionic polymer was synthesized by the reaction of poly (N-isopropylacrylamide-co-acryl acid) (poly (NIPAM-co-AA) with mono-6-ethanolamine-beta-cyclodextrin (EAA-beta-CD). EAA-beta-CD was synthesized via the reaction of mono-6-OTs-beta-CD (Ts p-toluensulfonyl) with EAA. The ionic polymer was characterized by means of FF-IR and UV-Visible spectroscopes and DSC. The result shows that the formation of ionic interaction between poly( NIPAM-co-AA) and EAA-beta-CD leads to an increase of the glass transition temperature (T-g) of poly (NIPAM-co-AA). In addition, not only the ionic polymer exhibits a well-defined lower critical solution temperature (LCST) but also beta-CD on the polymer backbone can be modulated by changing the pH values, as compared with beta-CD-conjugated polymers with covalent bonds. Also, beta-CD can easily be bound to the polymer backbone in form of free, or inclusion complex. It is expected that the polymer may find some useful applications such as drug delivery system.