Electrochemistry in Liquid Crystals: Orientational Effects in Electrochemical Processes

摘要

The electrochemical characterization of the room temperature nematic phases MBBA (p-methoxybenzilidene p-butyl aniline), MBAB (methoxy-butyl azoxybenzene) and K-15 (4-pentyl-4' cyano-biphenyl) has been performed in acetonitrile as well as in the neat phases and it is found that they all possess a wide range of potenitals over which electrochemical experiments can be carried out. MBBA and MBAB exhibit large ohmic drops making experimentation difficult. K-15, on the other hand, proved to be very well behaved. A number of model redox couples were investigated in k-15 and it is found that the electrochemical response can be significantly different from that observed in conventional solvents such as acetonitrile. These differences can be ascribed to the formation of ion aggregates as well as to differences in diffusion coefficients. We also present some preliminary findings on the effect of orientation on the observed electrochemical response of TCNQ (tetracyanoquinodimethane), ferrocene and TCNE (tetracyanoethylene).