Stress-Induced Collapse and Reactivity of Nanobubbles in Water: Linking Pressure Dynamics to Interfacial Stability

Nanobubbles exhibit anomalous stability in water, yet their response to external mechanical stress remains poorly understood. Here, we examine how mechanical impact and centrifugal compression affect nanobubble stability, collapse, and interfacial reactivity. Nanobubbles of air, CO₂, O₂, H₂, and N₂ were generated in water and subjected to drop impacts (0–15 m) and centrifugation (0–15,000g). Bubble size and concentration were measured by nanoparticle tracking analysis, while dissolved oxygen and terephthalic acid fluorescence quantified gas loss and hydroxyl radical formation. Both stress modes reduced nanobubble concentrations by up to 40%, with nonmonotonic size changes indicating destabilization and partial collapse. Dissolved oxygen decreased by 6–8%, and radical generation followed CO₂ > O₂ > air > H₂ > N₂, demonstrating gas-dependent interfacial reactivity. Pressure-energy analysis showed that external pressures (10⁴–10⁷ Pa) and dissipated energies (10–12 k_BT) match or exceed soft-particle eDLVO interaction barriers. These results show that nanobubble stability is governed by coupling.