Influence of solubilized stilbazolium salts in trans and cis configuration on the percolation equilibrium in AOT-isooctane-water microemulsions: Light induced switching of conductivity

Abstract

Solubilized trans and cis isomers of N-methyl and N-hexadecyl hydroxystilbazolium bromide had specific influences on the percolation temperature (as revealed by the onset of conductivity) in microemulsions composed of AOT, isooctane, and water: in the methyl derivative both cis-and trans-HSB induce shifts of the temperature at which conductivity sets on, the cis form being more efficient. In the hexadecyl compound a conductivity onset at increased temperature induced by the trans form was partially reverted when the cis isomer was present. Since trans → and cis stilbazolium salts can be interconverted photochemically, conductivity may be switched isothermally by exposing samples to light. Some competition between trans → cis photoisomerization and photodimerization was found depending on concentration ratios in the systems.