Synthesis and Properties of Mesogen-Jacketed Liquid Crystalline Polymers with Asymmetry Mesogenic Core

Abstract

Smectic A (SA) liquid crystalline phase developed from a new kind of mesogen-jacketed liquid crystalline polymer (MJLCP) whose mesogenic side groups are asymmetrically bonded to the main-chain was first reported. Two series of MJLCPs, poly[4,4‘-bis(4-butoxyphenyloxycarbonyl)-2-vinylbiphenyl] (PBP2VBP) and poly[4,4‘-bis(4-butoxyphenyloxycarbonyl)-3-vinylbiphenyl] (PBP3VBP) with different molecular weights were designed and synthesized via atom transfer radical polymerization successfully. The chemical structures of the monomers were confirmed by elemental analysis, mass spectrometry and 1H NMR. The molecular characterization of the polymers was performed with 1H NMR, gel permeation chromatography, and thermogravimetric analysis. Their phase structures and transitions were investigated by differential scanning calorimetry, wide-angle X-ray diffraction and polarized light microscopy experiments. The experimental results suggest that the polymer (PBP2VBP and PBP3VBP) with asymmetry mesogenic core can develop into a well-defined smectic A (SA) phase. This implies that the polymer molecules in the LC phase can be more ribbonlike rather than rodlike.