Temperature Sensitivity Study Of SBE-?-CD/P(NIPAM-co-QD) Composite System

Thermoresponsive polymers have become a research hotspot because of its unique properties. Among the thermoresponsive polymers, LCST of PNIPAM which is the favorite of the medicine field is closest to the human body temperature. Sulfonated butyl-beta-cyclodextrin (SBE-P-CD) has been widely used in drug release and biological materials because of its low toxicity. P(NIPAM-co-QD) and SBE-P-CD were designed and synthesized in the thesis, and then the thermoresponsive behavior of SBE-P-CD/P(NIPAM-co-QD) was studied. The main contents are as follows:N-isopropyl acrylamide was used to copolymerized with dimethylaminoethyl methacrylate, and by adding AIBN as initiator to prepare rondom and thermoresponsive copolymer P(NIPAM-co-DMAEMA), which was used to prepare P(NIPAM-co-QD) by quaternary ammonium reaction. The chemical structures of P(NIPAM-co-QD) and SBE-?-CD were well demonstrated with'H-NMR and FT-IR analysis. The thermal-sensitive experiment showed that P(NIPAM-co-QD) aqueous solution afforded gradually well-defined anti-sigmoidal transmittance-temperature (T-t) curves along with the increasing concentration of polymer and LCST was 31? or so. Zeta potential was tested by dynamic light scattering, shown that Zeta potential was increased upon the heating, for P(NIPAM-co-QD) water soluble segment curled and hydrophilicity of quaternary ammonium salt were distributed in the periphery of the PNIPAM aggregate,At the same time SBE-?-CD was synthesized. The LCST of P(NIPAM-co-QD) could also be tuned by changing the SBE-p-CD content in the SBE-?-CD/P(NIPAM-co-QD) mixture. The research showed that absorption intensity of benzene ring and fluorescence emission in?tensity of P(NIPAM-co-QD) decreased with decreasing concentrations of. P(NIPAM-co-QD) With addition of SBE-?-CD, absorption of benzene ring and fluorescence emission intensity of P(NIPAM-co-QD) were both increased due to SBE-?-CD changed state of aggregation of P(NIPAM-co-QD) in the water. As CSBE-?-CD/Cp gradually decreased, Zeta potential of SBE-?-CD/P(NIPAM-co-QD) changed from negative to positive charge, at last remained stable. By DLS measurements, particle size of SBE-?-CD/P(NIPAM-co-QD) upon heating became the initial steep build-ups, followed by rapid decline and final stable. Then the thermal-sensitive experiment showed the LCST of SBE-?-CD/P(NIPAM-co-QD) aqueous solution decreased from 6.7? and 24?. Obviously, it can adjust the LCST of quaternary ammonium salt type polymer by adding SBE-P-CD.