Interest in the use of poly(ethylene glycol-b-caprolactone) diblock copolymers for thermally triggered drug delivery has led to this study of the phase behavior of polymer micelles made from these diblocks. In aqueous solutions at concentrations above the critical micelle concentration (CMC), the polymer molecules assemble into micelles. Melting endotherms were observed in the DSC of the micelle solutions, indicating the polycaprolactone core was semi-crystalline. The degree of crystallinity depended on the methods used to prepare the polymer micelles. Furthermore, the degree of crystallinity depended on the degree of polymerization for the polycaprolactone block. The CMC slightly increased with increasing temperature as expected due to entropic effects. At temperatures above the melting point of the polycaprolactone core, there was greater increase in the CMC with increasing temperature. Dynamic light scattering showed the hydrodynamic diameter was independent of temperature, confirming that the micelles remained intact when the polycaprolactone core had melted.

On the phase behavior of polymer micelles having semi-crystalline cores

245th National Meeting (2013)

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