The strong attraction between hydrophobic moieties in aqueous solutions has been a topic of much interest due to the significance of the interaction in biological and industrial processes. In recent years, the attraction has been attributed to the nanobubble bridging mechanism. In this paper, atomic force microscopy was used to show that hydrophobic solid surfaces can repel each other by the nanobubbles. Specifically, different ethanol-water mixtures were used to investigate the nanobubble interaction force between a silica colloidal probe and a silica wafer rendered hydrophobic by esterification. Nanobubbles were produced on the solid surfaces by the solvent-exchange and surface scanning method. In pure water a strong, long range attractive force with a single jump in step was measured, typical of an interaction between two nanobubbles attached to the hydrophobic surfaces. The attraction was found to reduce with increasing ethanol concentration, changing to repulsion at ethanol concentrations above 40% by mass. A nanobubble capillary bridge model with constant bridge volume and contact angle was developed to explain the change in the interaction force with ethanol concentration. The bridge geometry, contact angle, volume and rupture distance were determined for different ethanol concentrations.