Estimation of the Stability of Foam Containing Hydrophobic Particles by Parameters in the Capillary Model.

The effect of hydrophobia particles on foam stability was quantitatively evaluated by the parameters in the capillary model. Polystyrene particles were dispersed into an ovalbumin solution, foam then being produced by introducing air into the ovalbumin solution with polystyrene particles (OSP) through a spinneret. The electric conductivity at selected positions in the foam and the drained liquid height below the foam were measured at constant intervals, the measured electric conductivity being converted to the OSP volume fraction in the foam. The capillary model described the OSP leakage rate from the foam and OSP volume fraction in the foam. As the particle concentration increased, the ratio of the OSP volume fraction in the foam to the volume fraction of the Plateau border, and time constant for drainage, Tincreased. This result indicates that the hydrophobic particles used stabilized the foam.