Soft Matter at the Thermal Scale, Ch Frank elasticity, defects and smectic layers
Problem
A planar nematic cell of a liquid crystal with dielectric anisotropy Δε=10.0 is placed between electrodes with the field normal to the plates. The measured Freedericksz threshold is Vc=0.65V, unchanged when the cell thickness is varied between 10 and 40μm. Using the Freedericksz threshold voltage Vc=πK1/ε0Δε, find the splay constant K1.