New chiral liquid crystalline systems: Imine monomers and side chain polymers

The research of the liquid crystal polymers has grown into field of science because liquidcrystal polymers combine features of both polymer and liquid crystal. Liquid crystal polymershave been anisotropy because of mesogenic units.Chiral liquid crystalline polymers have been the subject of many studies since 1978 whenRingsdorf and coworkers developed a new architecture for polymers entitled side chain liquidcrystal polymers. The low molecular mesogenic units have been used in the side chain liquidcrystal polymers. The mesogenic side groups bearing chiral centre have shown chiralmesophases. Liquid crystals and liquid crystal polymers have both been used in the displaytechnology.The aim of this work is the synthesis and characterization of liquid crystalline vinylmonomers having chiral imines and salysilaldimine mesogens and their homopolymers.For this purpose, liquid crystalline vinyl monomers having chiral imines and salysilaldiminemesogens were synthesized and their liquid crystal behaviours were studied. New side chainliquid crystalline homopolymers of liquid crystalline vinyl monomers having chiral iminesand salysilaldimine mesogens were prepared in the presence of AIBN as an initiator by usingfree radical polymerization route.The structures of the synthesized monomers having chiral imine and salysilaldiminemesogens and their homopolymers have been characterized by using spectroscopic methods(UV-VIS, IR, Proton-NMR, Carbon-13-NMR, MS). The molecular weight of the polymersdetected by using gel permeation chromatograpy (GPC) measurements. The thermal andmesogenic behaviours of the all synthesized monomers having imine and salysilaldiminemesogen and their homopolymers examined with differential scanning calorimetry (DSC)and polarization microscopy (PM) respectively. DSC and PM investigations of the monomersand homopolymers have shown that only salysilaldimine monomer and its homopolymershave been shown chiral smectic C mesophases.Keywords: Chiral Liquid Crystalline Polymers, Imine, Side Chain Liquid CrystallineHomopolymer.