The effect of n-alcohols on the force air bubble detachment from the surface of sulphur and graphite

Abstract

The force of air bubble detachment from sulphur and graphite surfaces was measured in aqueous solutions of methanol, ethanol and propanol in the concentration range 0 – 300 mg/dm 3. At the same time the angle was measured at the moment of rupture of the systems sulphur—air bubble—solution and graphite—air bubble—solution. From the results obtained it was found that the detachement force decreased as a function of alcohol concentration in water due to the occurrence of polar interactions at the sulphur—solution and graphite—solution interfaces. It was also found that the changes in the contact angle at the moment of rupture were similar to changes in the equilibrium contact angle in these systems. Thence, changes of F 0 values as a function of alcohol concentrations in water were calculated from the equation connecting the detachment force with the surface tension of the solution, the size of the contact plane area, the diameter of the bubble and the equilibrium contact angle. Calculated changes agreed with those found experimentally.