EXISTENCE OF CHARGED SUBMICROBUBBLE CLUSTERS IN POLAR LIQUIDS AS REVEALED BY CORRELATION BETWEEN OPTICAL CAVITATION AND ELECTRICAL-CONDUCTIVITY

It has been shown previously that in aqueous systems there exist charg ed gas-filled submicrobubbles (bubstons) associated in clusters that s erve as nuclei for optical cavitation [N.F. Bunkin, A.V. Lobeyev, B.W. Ninham and O.I. Vinogradova, Langmuir, submitted]. Here optical cavit ation as a function of temperature for a binary solution (with upper c ritical point) of polar liquids has been explored. For temperatures ab ove the binodal the cavitation probability is enhanced, and the format ion of a macroscopic bubble during the laser pulse is most likely due to coalescence of submicrobubble clusters. For temperatures below the binodal, the appearance of new phase droplets leads to a drastic decre ase in the cavitation probability. The effect is not associated with c hanges in concentration of the dissolved gas or to influence of solvop hobicity degree of the walls. The inhibited cavitation appears to be c losely connected with the decrease in the concentration of ions that h as been confirmed by simultaneous decrease in the electrical conductiv ity of the system. It has been shown that the results obtained constit ute indirect evidence for the existence in polar liquids of clusters f ormed just by charged submicrobubbles, or bubstons.