Light induced switching of conductivity in AOT-isooctane-water microemulsions via photoreactions of solubilizates

Small amounts of solubilized N-methyldiphenylamine or 9-hydroxymethylanthra cene and their photoproducts (N-methylcarbazole and photodimers of 9-hydrox ymethylanthracene, respectively) had specific influences on the percolation temperature (as revealed by the onset of conductivity) in monophasic micro emulsions composed of AOT, isooctane, and water: both the solubilizates ind uce shifts of the temperature at which conductivity sets on and affect the temperature of the border to the upper two phase region, 9-hydroxymethylant hracene being more effective. UV-irradiation in both cases lead to a decrea se of the percolation temperature by several degrees. Therefore conductivit y (percolation) can be switched isothermally from zero up to 3 mS cm(-1) up on exposure of samples to UV light. (C) 2000 Elsevier Science B.V. All righ ts reserved.