Adsorption and stabilization of surface nitrogen nanobubbles on mica

Nanobubbles are of critical importance in mineral flotation and surface cleaning, due to their high stability and large specific surface area. Surface nanobubbles have been most commonly observed on hydrophobic or weakly wetting substrates, such as graphite; however, substrate hydrophobicity is not a strict prerequisite for their stability. In this study, stable nanobubbles were experimentally observed on superhydrophilic muscovite, motivating an investigation of their interfacial stabilization mechanism. To elucidate this behavior, we investigate the adsorption and stabilization mechanisms of nanobubbles on the muscovite (001) surface using molecular dynamics simulations. The simulations demonstrate that nanobubbles can stably adsorb onto the mica surface, reaching an internal density of 443 kg m^-3. An interfacial water layer exists between the nitrogen gas and the interface, characterized by ordered hydrogen bond orientations and distinct hydrophobic properties, which collectively inhibit bubble diffusion and promote stability. Furthermore, the stable existence of nanobubbles on the mica surface was observed using quantitative nanomechanical atomic force microscopy (AFM). The stability of the nanobubbles is closely related to the structure of interfacial water, where high-density bubble structures, weak interlayer hydrogen bonding, and ordered hydrogen bond networks serve as the key factors for stable adsorption. These findings provide a theoretical foundation for understanding the microscopic mechanisms of nanobubbles at the solid-liquid interface.