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A series of novel liquid crystalline monomers based on N- substituted and 3-substituted pyrrole with varying the spacer length of alkylene and pentyl- or cyano- tail group on biphenyl mesogenic cores were synthesized. These monomers were polymerized by electrochemical method to yield conjugative polypyrrole with biphenyl-based mesogenic cores as the side groups.All the eight prepared monomers can be classified into two series; the first series is the N-substituted pyrrole: MPe- P-n (R = C5H11, n = 6,8 and 10) and MCN-P-n (R = CN, n = 6,8 and 10); the second series is the 3-substituted pyrrole: MAC-P (R = C5H11, n = 6) and MACCN-P (R = CN, n = 6). All the monomers, MCN-P-n and MACCN-P with cyano- tail groups exhibited nematic mesophase. In contrast, all the monomers, MPe-P-n and MAC-P with pentyl- tail groups showed smectic mesophase. Moreover, the monomer with cyano- group showed higher Ti than the respective monomer with pentyl- tail group.The polymers were formed electrochemically by cyclic voltammetry. For the reason of their insoluble and infusible. Structure of the polymers could only be determined by UV and IR spectra. Comparison with the current response indicated that N-substituted pyrrole forms electroactive polymer about 40 times faster than 3-substituted pyrrole. It was reversible and diffusion-controlled during polymerization. However, comparison with the time maintain electroactivity of polymer film showed that 3-substituted pyrrole was longer than N-substituted pyrrole.
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