The dielectric anisotropy Δε and threshold voltage Vth for electrically controlled birefringence have been measured for a series of nematic liquid crystals (binary mixtures of MBBA and PEBAB) with different negative Δε values. The threshold voltage varies as |Δε|−1/2, in agreement with theoretical predictions. The bend elastic constant K33 evaluated from these experiments is in order‐of‐magnitude agreement with recent measurements for pure MBBA.

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