Optical and thermal characterization of double hydrogen bonded liquid crystals: Binary mixtures

ABSTRACT

Methyl Malonic acid (MM) forms hydrogen bonds with octyloxy benzoic acid (8OBA), nonyloxy benzoic acid (9OBA), decyloxy benzoic acid (10OBA) labeled as MM+8OBA, MM+9OBA, and MM+10OBA respectively, all three mesogens exhibit mesogenic properties. Nine binary mixtures are prepared with MM+8OBA and MM+9OBA by varying their molar proportions in steps of 0.1 to 0.9. Similarly nine more binary mixtures are prepared with MM+8OBA and MM+10OBA. Two binary series namely MM+8OBA & MM+9OBA and MM+8OBA & MM+10OBA are analyzed. Various chemical and physical studies of these binary mixtures are investigated which includes Nuclear Magnetic Resonance spectral studies, FTIR, Polarizing Optical Microscopy and Differential Scanning Calorimetry. Phase diagram of above two binary series are constructed. Thermal studies derived from the DSC data include evaluation of order of phase transition, odd even effect, thermal stability factor, thermal equilibrium and variation of specific heat with temperature.

KEYWORDS:

• Hydrogen bonded liquid crystals
• binary mixtures
• Cox ratio
• specific heat
• thermal equilibrium

Acknowledgments

Blessings of Lordess Bannari Amman and Infrastructural support provided by Bannari Amman Institute of Technology are gratefully acknowledged.

Additional information

Funding

Financial support by SERB vide file no. EMR/2017/001075 is acknowledged.