ABSTRACT
Dynamic advancing contact angles were determined for the same solutions using an air bubble (0.3 to 0.6 mm long) trapped in a capillary filled with CTAB solution. The bubble is formed in the middle of the capillary, the ends of which are placed into vessels filled with the same solution. In this case, the rate of motion under applied pressure difference ∆P does not depend on the direction of the bubble motion. The intersection of the obtained v(∆P) dependencies measured for various concentrations of CTAB solution gives in this case only the difference between two tensions of wetting, γR cos θR−γA cos θA, which characterizes the hysteresis. The advancing angles are calculated using γR values obtained above and assuming γA=γo. The results of calculations are shown in Fig. 26 by curve 2. The maximum values of advancing contact angles correspond to the same region of CTAB concentration at about 10−5 M.
