A method for determining elastic constants of nematic liquid crystals at high electric fields

The elastic constants of liquid crystals are very important parameters for physical studies of liquid crystals and for liquid crystal displays. In this paper, a new method of determine the elastic constant ratio K-11/K-33 and the elastic constant K-11 of nematic liquid crystals by measurement of their optical retardation and capacitance at high electric fields is proposed. We derive theoretical formulas for the elastic constants, and then set up an optical retardation and capacitance measurement system. Finally, the experimental results for two commonly used liquid crystal compounds are discussed.