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 n ˆ shrinks on heating while it expands perpendicular to n ˆ . 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.