EXPERIMENTAL COMPARISONS WITH A NUMERICAL-MODEL OF SURFACTANT EFFECTSON THE BURST OF A SINGLE BUBBLE

A high-speed photographic study of gas bubbles bursting at a gas/liqui d interface in the presence of surfactant is described. Bubbles were b urst in a variety of media typical of those used in mammalian cell cul ture. In order to test the hypothesis that surfactant reduces cell dam age as a result of moderation of the bubble burst, a numerical simulat ion of the surfactant effect was compared with the experimental data. Surface tension, surface shear and dilatational viscosities were measu red in a variety of media containing a surfactant. The rate of bubble jet rise, a readily measured property of a burst, which depends strong ly on the presence of surfactant, was measured. Experimental observati ons in the presence of surfactant broadly agree with the theory in the reduction in jet rise rate, if it is assumed that dilatational viscos ity plays a major role. However, measured values for surface dilatatio nal viscosity were an order of magnitude less than those required for an observable effect in the model. A reason for this discrepancy is pr oposed. (C) 1997 Elsevier Science Ltd.