The effect of n-alkanes on the force of air bubble detachment from the surface of graphite in water

Abstract

Measurements of the force of air bubble detachment from graphite surface wetted with n-alkane (in homologous series from hexane to hexadecane) in water were carried out; it was found that the detachment force as a function of the chain length of the hydrocarbons changes discretely, probably because of a different film structure of even hydrocarbon and the neighboring odd one. It was shown that the detachment force depends on the film thickness and that an optimal thickness exists for every n-alkane, for which maximal stability of a three-phase systems occurs. The stability of the system graphite/ n-alkane film—air bubble—water can well be calculated on the basis of the contact angle value in this system from the equation relating the magnitude of the detachment force with the area of the contact plane, the size of air bubble, and contact angle value.