High-resolution calorimetric study of the phase transitions of tridecylcyanobiphenyl and tetradecylcyanobiphenyl liquid crystals

Abstract

A thermal study of the liquid crystals tridecylcyanobiphenyl and tetradecylcyanobiphenyl has been performed by means of adiabatic scanning calorimetry. Both compounds exhibit only the smectic-A mesophase between the normal liquid and the crystalline phase and their phase transitions are strongly first order. A summary of the enthalpies and transition temperatures for all the smectic homologues of the cyanobiphenyl family is given, based on high-resolution measurements of the present work and previous studies.

Keywords:

• adiabatic scanning calorimetry
• 13CB
• 14CB
• specific heat capacity
• enthalpy

Acknowledgements

G. Cordoyiannis acknowledges the receipt of a postdoctoral fellowship of Research Fund of K.U. Leuven and FWO research project G.0230.07, as well as K. Binnemans for useful discussions.