含羞草视频 this event

Abstract

A fundamental tenet of materials science is that properties, morphology, and chemistry are all interdependent. The ability to design new materials with desirable properties relies on a thorough understanding of the underlying mechanisms that give rise to those characteristics. Small-angle scattering is a powerful tool for assessing sub-micron structure in polymers and other materials. Small-angle X-ray scattering (SAXS) offers analysis based on differences in electron density while small-angle neutron scattering (SANS) gives information based interactions with atomic nuclei, providing complimentary experimental tools for morphological characterization. High flux sources further enhance this capability by offering the possibility of monitoring structural changes in situ during mechanical, thermal, and other testing protocols.

In this presentation, three different projects which utilize structural characterization though small-angle scattering are described. In the first, the effect of incorporating a novel cationic moiety to a standard polyurethane formulation as a chain extender was explored for applications including polymer electrolyte membranes in alkaline fuel cells and selective water vapor transport membranes in garments for hazardous environments. In the second, the effect of using a metal-binding ligand as a chain extender in a polyurethane is explored. These materials offer interesting possibilities for tuning mechanical and dynamic behavior simply by the addition of metal salt to form non-covalent intermolecular bonds. In the third project, SANS was used to understand the morphological behavior of a series of tough hydrogels designed to have ultrahydrophilic properties for hemorrhage control applications.