Synthesis and Surface Characterizations of New Banana-Shaped Liquid Crystal 4-Bromo-1,3-phenylene-bis[4-[4′-(10- undecenyloxy)-benzoyloxy]]benzoate

Abstract

A new banana-shaped liquid crystal compound, i.e., the bent-core mesogen, 4-Bromo-1,3-phenylene-bis[4-[4′-(10-undecenyloxy)-benzoyloxy]]benzoate (BPUBB), has been synthesized and characterized. Phase transition temperatures of BPUBB were determined by polarizing microscopy and differential scanning calorimetry. The inverse gas chromatography method was utilized to obtain the surface characterization of BPUBB. This compound was used as a stationary phase in the chromatographic column and nine solutes with a different chemical nature were used as eluents. The dispersive component of the surface free energy, γ ^D _S , of studied adsorbent surface was estimated using retention times of different nonpolar organics in the infinite dilution region. The specific free energy of adsorption, ΔG^S _A , the enthalpy of adsorption, ΔH^S _A , and the entropy of adsorption, ΔS^S _A , of solvents on liquid crystal were determined. The values of the ΔH^S _A were correlated with both the donor and the acceptor numbers of the probes to quantify the acid K_A and the basic K_D parameters of the liquid crystal surface. The values obtained for the K_A and K_D parameters indicated a basic character for the surface of the BPUBB.

Keywords:

• Inverse gas chromatography
• Lewis acid-base constants
• liquid crystals
• surface and adsorption properties
• surface free energies

Acknowledgment

This research has been supported by the Yildiz Technical University Scientific Research Projects Coordination Department.