New Liquid-Crystalline Elastomers: 1. Synthesis, Structure, and Phase Behavior of a Series of Mesogenic Crosslinking Agents Containing Reactive Bifunctional Groups

Abstract

The synthesis of eight mesogenic crosslinking agents (1c−8c) containing reactive bifunctional groups is described. The chemical structures were characterized by Fourier transform infrared (FTIR) and ¹H nuclear magnetic resonance (NMR) spectra. The mesomorphism was investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). The compounds 1c, 2c, 3c, 5c, 6c, and 8c showed an enantiotropic nematic phase. In addition, 5c exhibited a smectic A (SmA) phase on cooling; 4c exhibited a smectic C (SmC) phase, a SmA phase, and a nematic phase and a monotropic a smectic B (SmB) phase on cooling. 7c revealed an SmA phase and a nematic phase and a monotropic SmC phase on cooling.

Keywords:

• Crosslinking agent
• liquid crystalline
• nematic phase
• reactive bisfunctional group
• smectic phase

Acknowledgment

The authors are grateful to the Educational Development of Liaoning Province, China for financial support of this work.

Notes

K = crystal, N = nematic, SmA = smectic A phase; SmB = smectic B phase; SmC = smectic C phase; I = isotropic; D = decomposition.