Estimation of thermodynamic and Beyer's parameter (B/A) in liquid crystalline 5.m, 5O.m, 5.Om, 5O.Om compounds with m=5 and 16

The thermodynamic parameters such as Sharma parameter (So), Huggins parameter (F), reduced volume (V˜), reduced compressibility (V˜C1), etc. are studied using the volume expansion coefficient (α), which is estimated from density for N-(p-n-pentyl benzylidene)-p-n-pentyl aniline (5.5), N-(p-n-pentyloxy benzylidene)-p-n-pentyl aniline (5O.5), N-(p-n-pentyl benzylidene)-p-n-pentyloxy aniline (5.O5), N-(p-n-pentyloxy benzylidene)-p-n-pentyloxy aniline (5O.O5), N-(p-n-pentyl benzylidene)-p-n-hexadecyl aniline (5.16), N-(p-n-pentyloxy benzylidene)-p-n-hexadecyl aniline (5O.16), N-(p-n-pentyl benzylidene)-p-n-hexadecyloxy aniline (5.O16) and N-(p-n-pentyloxy benzylidene)-p-n-hexadecyloxy aniline (5O.O16) compounds in isotropic and liquid crystalline phases. The parameters like intermolecular free length (Lf), molecular radius (mr) and Beyer's non-linearity parameter (B/A) are also computed from density data for the above compounds. The results are discussed in the light of these parameters variation with temperature in a particular phase in a liquid crystal molecule and with the position of oxygen atom. The thermodynamic parameter So exhibits a constant characteristic value 1.11±0.01 in all the compounds like other reported liquid crystalline compounds, liquids and polymers. The variation of other thermodynamic parameters in LC phases of these compounds with temperature is discussed in the light of the body of the data available.