Optically active electrochromic polymer films from cyclopenta [2,1-b;3,4-b′]ditiophene prepared in chiral liquid crystal with molecular asymmetry imprinting polymerization

Cyclopenta[2,1-b;3,4-b ']dithiophene (CPDT) based chiral electrochromic (EC) polymer films were synthesized by electrochemical polymerization (EP) in cholesteric liquid crystals (CLCs). We prepared several types of monomers to investigate effects of their planarity and compatibility with host liquid crystals (LCs) on the per-formance of these polymer films. EP in CLCs had succeeded in imparting chirality transfer to the resultant EC polymer films. Especially, the CPDT-based polymer with methyl group (dMCPDT) showed a large red-shift in the absorption wavelength due to the pi-pi * transition, and clear circular dichroism (CD). This is because dMCPDT had improved compatibility with the host LCs while maintaining high planarity derived from CPDT backbone. In addition, CPDT with 3,4-ethylenedioxythiophene (EDOT) introduced at both ends resulted polychromaticity by voltage scanning. Furthermore, the CPDT-based polymer has excellent electrochromic properties, fast response time and high cycle stability were observed. Imparting functionality to CPDT-based polymers with high planarity and high charge mobility is preferred for practical electronic device fabrication.