N-isopropylacrylamide copolymers with acrylamide and methacrylamide derivatives of cholic acid: Synthesis and characterization

By free radical polymerization, we have prepared a series of water-soluble, thermosensitive copolymers based on N-isopropylacrylamide and (meth)-acryl amide derivatives of cholic acid, one of the bile acids. The copolymers con tained 1-7 mol-% of the (meth)acrylamide derivatives of cholic acid. The ch emical composition in the copolymers was studied by NMR spectroscopy and wa s found to be close to the original composition of the comonomers in the fe ed prior to polymerization. The lower critical solution temperatures (LCST) of the polymer solutions were measured by means of differential scanning c alorimetry and turbidimetry. The resulting copolymers exhibit systematic ch anges in their LCSTs as a function of their chemical composition, as the in corporation of hydrophobic comonomers leads to a lower LCST.