DOW Graduate Seminars: The Rheology of Colloidal and Nanoparticle Dispersions: "STF Armor" - Nanoparticle Composites for Flexible Ballistic Materials

Event Date: February 19, 2008
Speaker: Norman J. Wagner, Alvin B. and Julia O. Stiles Professor and Chair
Speaker Affiliation: Department of Chemical Engineering, University of Delaware
Time: 3:30 - 4:30 pm
Location: FRNY G140

Colloidal and nanoparticle dispersions can exhibit shear thickening, which is an active area of research with consequences in the materials and chemical industries, as well as an opportunity to engineer novel energy adsorbing materials. A fundamental understanding of shear thickening has been achieved through a combination of model system synthesis, rheological, rheo-optical and rheo-small angle neutron scattering (SANS) measurements, as well as simulation and theory.

Novel ballistic, stab and impact resistant flexible composite materials are synthesized from colloidal & nanoparticle shear thickening fluids (STFs). Through ballistic, stab & laboratory testing, the mechanism of energy adsorption at ballistic rates is demonstrated to result from reversible shear thickening. As a basis for the rational design of flexible ballistic & stab resistant materials, we report a rheological and microstructural investigation of the high shear rheology of colloidal and nanoparticles dispersions. Control of particle size, size distribution, shape, surface and bulk properties is shown to be critical to performance. Statistical mechanical modeling provides a framework for the rational design of materials to meet specific threats. Potential applications of these dispersions as novel energy absorbing materials are discussed, including commercial body armor.