Coalescence characteristics of bulk nanobubbles in water: A molecular dynamics study coupled with theoretical analysis

Nanobubble coalescence is a process of great importance to a broad range of applications such as froth flotation of fine or ultrafine mineral particles, detergent-free cleaning of clothes, and de-inking of recycled papers. To investigate the differences between nanobubble coalescence and macrobubble coalescence, we use molecular dynamics simulations and theoretical analysis to study the coalescence characteristics of bulk nanobubbles in water. We provide quantitative evidence showing nanobubble coalescence characteristics universally deviate from macroscopic bubble theories due to the small bubble size and the unique effects of Laplace pressure in nanobubbles.