Effect of fluorine substitution on the core geometry and refractive indices in biphenyl-cyclohexane liquid crystals: A DFT study

Abstract

Incorporating fluorine into liquid crystalline molecules has been found to bring about desirable changes to their physicochemical properties to improve the behavior of the parent compound. This paper attempts to determine the effect of fluorine incorporation on refractive indices in biphenyl-cyclohexane (BCH) liquid crystals. To understand the mechanisms of the effect, quantum chemistry calculations were carried out. For the investigated liquid crystals, refractive indices are estimated through the calculated molecular polarizabilities at different optical wavelengths. Through a systematic relationship between the fluorine substituents and the optical constants, it has been demonstrated that the refractive indices of the investigated liquid crystals do not change largely in the studied wavelength range. However, the fluorine substituents significantly affect refractive indices. The effects of fluorine substitution on the core geometry are also examined.