Amplified stain-rate dependence of deformation in polymer-dispersed liquid-crystal materials

The mechanical properties of polymer-dispersed liquid crystals (PDLCs) are investigated to elucidate their fundamental microstructural and mechanistic underpinnings, and overall structural integrity under deformation. High st rain-rate loading experiments and quasistatic compression tests on PDLC mat erials reveal an amplified strain-rate dependence relative to the matrix ma terial. A finite-element micromechanical model of PDLC materials explains t his behavior in terms of strain-rate concentrations at the equators of the spherical liquid-crystal droplets. The model also predicts a weak dependenc e of the aspect ratio of deforming liquid-crystal droplets on their volume fraction. (C) 1999 American Institute of Physics. [S0003-6951(99)04439-3].