Structure and Self-Assembly of Thermoreversible Triblock Copolymer Micelles and Gels

The polymer physics of hierarchical, self-assembled block copolymer solutions remains an active area of research for both advanced materials and biomaterial applications. Of current interest is the development of aliphatic polycarbonates for biomedical applications [1]. For instance, cholesterol-functionalized aliphatic polycarbonate diblock copolymers of polyethylene glycol formed disk and stacked disk-like self-assembled morphologies that are nano-carriers for hydrophobic molecules [2]. The hydrophobic nature of the cholesterol block provides a versatile platform to form complex morphologies in solution. The presentation will describe the phase diagram, structure and dynamics of the micelles and gels formed by well-defined triblock copolymers prepared with cholesterol and fluorene hydrophobic end-groups. The hierarchical structure of these thermoreversible gels as a function of hydrophobic end-group molecular weight was studied by small-angle neutron scattering and static and dynamic light scattering covering nm-to-micron length scales and microsecond-to-second time scales. [1] F. Suriano, O. Coulembier, J.L. Hedrick, P. Dubois, Polym. Chem. 2, 528 (2011). [2] S. Venkataraman, A.L. Lee, H.T. Maune, J.L. Hedrick, V.M. Prabhu, and Y.Y. Yang, Macromolecules 46, 4839 (2013).