Zeta potential of insoluble monolayer of long-chain alcohol at the air-aqueous solution interface

The zeta potential of a close-packed insoluble monolayer of 1-hexacosanol a t the air-water interface in the presence of 0.001 M NH4NO3 was measured as a function of pH by means of the plane interface technique. The negative z eta potential increased with the increase of pH up to about 9. The negative charge at the monolayer-water interface is considered to be due to the dis sociation of protons from hydrated alcohol water clusters at the surface. T he zeta potential results were analyzed in terms of the site dissociation a nd site-binding mechanism within the Gouy-Chapman-Stern-Grahame double-laye r model of the metal oxide-water interface. (C) 2001 Academic Press.