Synthesis and study of calixarene-core polylactide star polymers and related amphiphilic block copolymers

CHED 820

Ray D. Dria, Beverly A. Goudy, and Perry S. Corbin. Department of Chemistry, Ashland University, 401 College Avenue, Ashland, OH 44805
The biocompatible/biodegradable polymers, polylactide, polyglycolide, polycaprolactone, and amphiphilic block copolymers formed therefrom have been employed in a number of biomedical applications. To expand architectural diversity within this class of macromolecules, we have synthesized calixarene-core polylactide star polymers with narrow polydispersity indices. In short, homopolymers have been prepared by Sn(II)-catalyzed, ring-opening polymerization of DL-lactide using a tetra-functional, calixarene initiator. To produce amphiphilic diblock copolymers, selected polylactides were derivatized via carbodiimide-mediated coupling of the chain-ends of the star polymer arms to the carboxyl-terminus of a modified poly(ethylene glycol). Preliminary results suggest that the aforementioned copolymers are produced with reasonably high coupling efficiencies and that the amphiphiles self-assemble to form micelles in dilute aqueous solution. Further characterization is underway in efforts to develop a novel, micelle-based drug-delivery system. Moreover, it is anticipated that a variety of functional groups may be integrated in calixarene-core polylactides, affording building blocks for diverse materials applications.