Bubble Formation on a Hydrophobic Surface

Abstract

This work studies the formation of a charged equilibrium nanobubble on a smooth hydrophobic solid–water interface. Expressions are given for the change in the Gibbs energy of the system, taking into account the Kelvin capillary equation, the electrostatic energy of the electrical double layer at the bubble-water interface, and the surface energy. The graph of the Gibbs energy versus the nanobubble radius is shown to have a minimum, which indicates the possibility of spontaneous generation of these nanostructures. The work studies the dependence of Gibbs energy on the contact angle, as well as salinity and the coefficient of surface tension, and calculates the surface charge necessary for the stability of nanobubbles.