Diffusion of low molecular polymers through tunable phase separated morphology

Based on phase diagrams measured for ternary blends, specific phase separated morphologies have been prepared. These morphologies are useful for controlling migration of molecules or low molecular weight polymers. The applications in our laboratory include drug delivery and curing behavior of reactive prepolymers. This talk will focus on blends including crystallizable polyesters, e.g poly(lactic acid), with a number of small molecules or low molecular weight polymers. Generally the mixtures can also include a solvent of various quality. The morphology formed is dependent on the equilibrium phase diagram and kinetics associated with solvent removal. The migration of specific components is highly dependent on chain dynamics. The stability of such morphology as a function of time and temperature is also an important consideration and relates to chain dynamics. Based on our previous studies, we provide an explicit molecular model to explain PLA chain dynamics. The diffusion behavior of low molecular weight polymers is found to depend on both single chain dynamics and macroscopic morphologies. A relationship between the phase separated morphology and their formation to the overall migration dynamics will also be discussed.