Synthesis and properties of novel thiophene-based liquid crystalline conducting polymers (LCCPs)

Roudini, Danesh (2015) Synthesis and properties of novel thiophene-based liquid crystalline conducting polymers (LCCPs). (PhD thesis), Kingston University, .

Abstract

Side chain liquid crystalline polythiophenes have been synthesised and investigated in order to study the effects of liquid crystalline moieties on the polymer and their possible effect on the electronic properties. Initially some mesogenic groups with a structure of two benzene rings were synthesised as the rigid core of the mesogen. This synthesis was followed by the attachment of mesogens through a six-methylene unit spacer to 3-thiophene methanol and the preparation of thiophene-based monomers. The chemical structure of the prepared monomers was confirmed by characterisation techniques such as NMR, GCMS and ATR etc. The investigation of the liquid crystalline behaviour of the monomers was carried out by polarised hot-stage optical microscopy (HSM), differential scanning calorimetry (DSC) and X-Ray diffractometry (XRD) The resulting monomers were polymerised chemically into the form of powders in order to measure their conductivity. A thin film of polymers was prepared on silicon and ITO glass substrate. The liquid crystalline properties of the polymer films were studied using DSC and HSM. XRD was used to investigate the effect of a magnetic field on the monomers and polymers. Polymerisation and electroactivity of monomers were studied on an ITO glass substrate by cyclic voltammetry technique. Polymers were modelled using Quantum Cache (Scigress) to predict their geometry and the calculated molecular dimensions were compared with the results of the X-ray diffraction analysis.

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