The Temperature Dependence of the Orientational Order Parameter of the Mesogens : 4'-n-Propyl Phenyl-4-(4'-n-Pentyl Cyclohexyl) Benzoate, Trans-4-Propyl Cyclohexyl 4-(Trans-4-Pentyl Cyclohexyl) Benzoate and 4-Pentyl Cyclohexyl-4-(4-Propyl Cyclohexyl)

摘要

The birefringence 'properties of the three mesogenic compounds 4'-n-propyl phenyl-4-(4'-n-pentyl cyclohexyl) benzoate (code name HP53) Trans-4-propyl cyclohexyl 4-(trans-4-pentyl Cyclohexyl) Benzoate (code name HH53) and 4-Pentyl cyclohexyl-4-(4-propyl cyclohexyl) Benzoate (code name HD35) have been studied as a function of temperature. The variation of polarisibilities with temperature of the three mesogens has been calculated from birefringence studies and the orientational order parameter thereby determined as a function of temperature. Texture studies have been conducted to confirm/ identify the different mesophases of HP53 and HH53. The two smectic phases 1 and 2 of HD35 have been identified, as the smecticE and smecticB phase from texture and x-ray studies [1]. Comparison has been made of values of the three mesogens. Also values of HD35 obtained from the above study have been compared with values of the same obtained from x-ray methods [1].