Thermo-mechanical properties of tri-functionally crosslinked liquid single crystal elastomers

We have investigated thermo-mechanical properties and optical birefringence of the V3 cross-linker liquid single crystal elastomers (V3LSCEs) with different concentrations of the flexible tri-functional cross-linker as a function of temperature. The length of V3LSCEs along the director nˆ shrinks on heating while it expands perpendicular to nˆ. Drastic length changes as well as large variations in the optical birefringence, Δn, are observed near Tc. The maximum contraction increases with increasing cross-linking concentration. When the anisotropy of the shape change is plotted as a function of Δn, a linear dependence is observed only deep in the nematic phase for larger cross-linking concentrations.