Effect of molecular flexibility on the nematic–isotropic phase transition: An improved analysis

Experimental studies have shown that the chain configurations play an important role in the properties of the nematic to isotropic phase transition. We extend the Landau-de Gennes theory to describe the molecular flexibility on the nematic to isotropic phase transition. The effect of molecular flexibility is to modify the Landau coefficients and to change the character of the transition. The Landau coefficients are calculated for various chain lengths from the experimental data. The theoretical predictions are found to be in good qualitative agreement with available experimental results.

► The effect of molecular flexibility on the nematic–isotropic transition is discussed.
► The character of the first or second-order transition is explored.
► The Landau coefficients are calculated.