Synthesis of ferroelectric liquid-crystalline polymethacrylates containing 1,2-diphenylethane based mesogens

✍ Scribed by Chain-Shu Hsu; Bin-Sheng Her

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 711 KB
• Volume: 197
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1996.021971211

✦ Synopsis

Abstract

The synthesis of side‐chain liquid‐crystalline polymethacrylates containing (2__S__)‐2‐chloro‐4‐methylvaleric acid end groups and 1,2‐diphenylethane based mesogenic units is presented. Differential scanning calorimetry, optical polarizing microscopy and X‐ray diffraction were used to determine the thermal transitions and to analyze the anisotropic phases. Among the methacrylate monomers prepared in this study, those without lateral chloro substituent show only a smetic A phase while those with a lateral chloro substituent display a cholesteric phase. All polymers exhibit smectic mesomorphism and do not undergo side‐chain crystallization. All four polymethacrylates without lateral chloro substituents reveal enantiotropic smectic A and smectic B phases while the other four polymethacrylates with lateral chloro substituents reveal enantiotropic smectic A and chiral smectic C phases. The results seem to demonstrate that incorporating a lateral chloro substituent into the mesogenic core enhances the formation of a tilted chiral smectic C phase.