EFFECT OF THE ELECTROSTATIC POTENTIAL OF MICROEMULSION DROPLETS ON PHOTOPROTOLYTIC DISSOCIATION OF 1-NAPHTHOL

It was possible to give drops of the disperse phase an electrostatic p otential phi that varied within +/-2.50 mV (for the same drop size) by adding small amounts of electrolytes containing a strongly hydrophobi c ion and a hydrophilic counterion to an uncharged microemulsion (ME) of the oil/water type. The phi experimentally determined for negativel y charged drops are in satisfactory agreement with the calculation bas ed on a previously examined model. The kinetics of the model reaction of photodissociation of 1-naphthol located in ME drops were investigat ed in the entire range of potentials and a seven-fold change was obser ved in the dissociation rate constant. A model that includes reversibl e proton transfer in a complex with a hydrogen bond and separation of an ion pair as a result of diffusion of H3O+ was examined for explaini ng these effects. Migration of H3O+ away from the drop nucleus is hind ered when phi decreases, but lateral migration is still possible.