Thin liquid films from dilute sodium dodecyl sulfate solutions formed on amercury electrode

The stability and rupture of thin aqueous films formed between a hydrogen b ubble and a mercury droplet were studied in aqueous solutions of 5 x 10(-6) or 10(-3) M sodium dodecyl sulfate in the presence of 0.05 M Na2SO4. The m ercury droplet was positively polarized at E = 0.2 V in the rational potent ial scale. The critical thickness of film rupture, or the equilibrium thick ness of stable films, was measured using the microinterferometric method. R esults were discussed in terms of DLVO and heterocoagulation theory by refe rring to the differential capacity previously reported.