Liquid-crystal-imprinted synthesis of chiral polypyrroles without a chiral centre using a two-step method of spark-discharge oligomerisation-electrochemical polymerisation

Pyrrole in a cholesteric liquid crystal was discharged using a Tesla coil to generate pyrrole radicals, affording linear-shaped nano-ordered pyrrole oligomers. Subsequently, the electrochemical polymerisation of a pre-oriented pyrrole oligomer having good affinity for liquid crystals was performed to achieve polypyrrole-imprinted asymmetry from the cholesteric liquid crystal structure. The resultant polymers were analysed using polarising optical microscopy observations, scanning electron microscopy, electrochemistry, optical spectroscopy, and electron spin resonance. The combination of spark discharge and electrochemical polymerisation is useful for conveniently transferring the liquid crystal structure to the main chain of polymers.