Polymers made from cholic acid derivatives: selected properties

Polymers of methacrylate and methacrylamide derivatives of cholic acid were prepared by free radical polymerization in solution. To verify the stereoisomeric effect of the monomeric units, certain properties of the resulting polymers were compared, including conversion rate, molecular weight, and glass transition temperature. The 3β-epimers of the methacrylates and methacrylamides are to polymerize more easily than the 3α-epimers. Water absorption experiments showed that the methacrylamide polymers are more hydrophilic than the methacrylate polymers and that the polymers from the 3β-epimers have higher hydrophilicity than those made from the 3α-epimers. The free acid forms of the polymers were also prepared by selective hydrolysis of the methyl ester group of the cholic acid moiety which resulted in improved hydrophilicity of the polymers.