UNIQUE ELECTRICAL AND OPTICAL-PROPERTIES OF CONDUCTING POLYMERIC LIQUID-CRYSTAL

Electrical conductivity of poly(bis(4-methoxy-4'-hexyloxy biphenyl)-dipropargyl malonate) (PMHBDPM) exhibits unique temperature dependence corresponding to the phase transitions. Thermochromism and solvatochromism are not observed in PMHBDPM. However, unique electrochromism has been observed. That is, with increasing doping level, PMHBDPM changes color from red in the non-doped state to colorless and then to blue in the highly doped state. Not only the conjugated main chain, but also the biphenyl unit in the side chain, are thought to play roles in the doping phenomenon. ESR (electron spin resonance) spin density as well as linewidth changed markedly with electrochemical doping. These characteristics have been discussed in terms of the soliton model.