(713i) Phase Morphology in Polymer Matrix Composites and Blends Using Neutron and X-Ray Scattering

Polymer matrix composites have applications in aerospace, construction, pharmaceuticals, medical devices, and more. Their composition includes a dispersed material that provides a desired functionality to the polymer (e.g. increased strength) or that benefits from the presence of the matrix material (e.g. improved phase stability of dispersed component). Our past work has focused on understanding the effect of polymer-polymer and polymer-solvent interactions on the final, solid-state phase morphology and performance of polymer composites comprised of a commodity polymer matrix and a dispersed conjugated (semi-conductive) polymer. These blends are of interest for organic electronic devices as the matrix component adds mechanical durability and extends device lifetimes while the conjugated component has been found to maintain performance at weight fractions as low as 1-10 %. It can be difficult to study these materials with common microscopy techniques due to limited contrast between the organic phases and their opaque color, but by use of a deuterated matrix phase, small angle and ultra-small angle neutron scattering can characterize the phase separated domains and self-assembled nanofibers of the conjugated polymer. Together with wide-angle X-ray scattering and conductivity measurements, we used neutron scattering to develop an understanding of the blend morphology as a function of processing conditions and its relationship to film performance (i.e. conductivity). Here we will first provide a review of our past work on commodity and conjugated polymer composites. We will then provide a discussion on the extension of these concepts to our current work focused on polymer matrix composites with a small molecule dispersed phase, i.e. amorphous solid dispersions. Most of today’s drug candidates have low water solubility, which limits their bioavailability and uptake in vivo. Amorphous solid dispersions can improve drug dissolution by kinetically trapping amorphous domains of these active pharmaceutical ingredients on the order of nanometers to micrometers in a polymer matrix. However, the efficacy and stability of these formulations are dependent on the phase morphology, while is further influenced by molecular interactions between the drug and matrix phases as well as the thermal and mechanical conditions during processing. In this work, we use both neutron and X-ray scattering to develop an understanding of this relationship to inform improved amorphous solid dispersion formulations in the future.