Universality of the nematic mesophase.

This paper presents a detailed comparative study of published order-parameter experimental data of nematic liquid crystals. Throughout a simple linear transformation, it is shown that three distinct nematic mesophases exhibit the same and unique universal behavior for all temperatures below the nematic-isotropic phase transition. This paper generalizes a previous one [M. Simões, D. S. Simeão, S. M. Domiciano, and A. de Campos, Phys. Lett. A 372, 5346 (2008)], in which only the nematic mesophase delimited by the crystalline phase at low temperature was studied. Here we have assembled order-parameter experimental data of 61 different compounds, forming a set with data of 96 experiments, aiming to show that the nematic universal behavior is independent of what is the actual phase or mesophase bordering the nematic phase at low temperatures; our results show that all experimental data of all nematic mesophases coalesce along a common line that extends over the entire range of mesophases.