Plasmonic nanobubble formation and development: A lattice Boltzmann simulation

Plasmonic photothermal nanobubble exhibits excellent potential in numerous fields. Due to involving photothermal conversion, heat transfer, and phase change, the nanobubble formation process is extremely intricate. Therefore, it is necessary to investigate the formation mechanism of nanobubble comprehensively. In this work, the transient formation and evolution of nanobubbles generated by gold nanoparticles immersed in water excited by laser are investigated based on the Lattice Boltzmann method. Considering the variation of the physical property of water during the phase change, the role of the interfacial thermal conductivity on the transient transfer heat dynamics is analyzed. It is found that for high interfacial thermal conductivity, the temperature rise rate of water adjacent to the nanoparticle surface may be weakened. Moreover, considering the phase change, physical parameter variation, and the interplay between thermal diffusive losses and light absorption of gold nanoparticles, the dependence of nanobubble volume and nanobubble nucleation fluence threshold on nanoparticle size do not match with each other. The nanobubble nucleation fluence threshold on hydrophobic to hydrophilic surfaces is also investigated. The heat transfer between nanoparticles and water is hindered because of the wetting layer on the hydrophilic surface. Therefore, it is an effective way to reduce the fluence threshold by increasing the interfacial thermal conductivity of the hydrophilic surface. This work provides theoretical guidance for the flexible control of plasmonic nanobubbles.