Investigation of Structure and Dynamics in Novel Nanocomposite Membranes

Investigation of Structure and Dynamics in Novel Nanocomposite Membranes ABSTRACT The introduction of nanoscale structure in polymers can lead to dramatic enhancements in the bulk properties of the resulting materials. The inclusion of nanoscale filler particles, for example, creates vast amounts of particle-polymer surface area, and particle-polymer interactions, as well as physical confinement effects, can produce conformational changes at the nanoscale that are often manifested in substantial improvements in the macroscopic performance of the nanocomposites. In this proposal, we seek to exploit recent discoveries revealing that the inclusion of nanoscale particles in the polymer matrix can result in significant improvements in the performance of rubbery gas separation membranes. By undertaking a fundamental investigation of the structure, dynamics and permeation properties of a series of strategically formulated model nanocomposites, we will elucidate the underlying chemical and physical factors that govern nanocomposite morphology, polymer mobility, and their correlation with gas transport. Of particular interest is the ability of the particles to alter molecular-level chain packing and corresponding polymer chain dynamics. Broadband dielectric spectroscopy and dynamic mechanical analysis will provide detailed information on the dynamic character of the polymer chain segments across a wide range of experimental timescales, affording direct insight as to the influence of local confinement on polymer chain motion and its relationship to penetrant permeation. These studies will contribute to our molecular-level understanding of structure development and dynamics in polymer nanocomposites, as well as to the establishment of fundamental design rules for the optimization of transport performance in nanoscale heterogeneous materials.