The use of shear thickening nanocomposites in impact resistant materials.

The work presented here demonstrates using a novel, field-responsive nanocomposite based on shear thickening fluids (STFs) as responsive protective materials with superior damping and energy adsorption properties. Peak forces and accelerations measured using an instrumented Instron drop tower demonstrate that STF nanocomposite prototypes and impact foam taken from a commercial football helmet have similar performance for low kinetic energy impacts. However, tests with STF nanocomposite samples exhibit significantly reduced peak acceleration and peak force for impacts above 15 J.

Impact of diblock copolymers on droplet coalescence, emulsification, and aggregation in immiscible homopolymer blends.

Using rheo-optical techniques, we investigated the impact of interfacial wetting of symmetric diblock copolymers (BCPs) on the coalescence and aggregation of polydimethylsiloxane (PDMS) droplets in immiscible polyethylene-propylene (PEP) homopolymers. Anionic polymerization was used to synthesize well-defined matrix homopolymers and symmetric 16 kg/mol-to-16 kg/mol PDMS-b-PEP diblock copolymers with low polydispersity (PDI ≈ 1.02) as characterized with size exclusion chromatography and nuclear magnetic resonance spectroscopy.