Radiative nanobubbles in aqueous solutions: Rayleigh instability sustains resonant oscillations and potential...

Vibrational treatment increases gas nano- and microbubble content in aqueous environments. Nanobubbles stabilized by ions (bubstons) generate electromagnetic waves in the GHz range during regular oscillations and can reversibly capture secondary electrons by their boundary hydration shells. We hypothesize that these emissions facilitate long-range interactions between aqueous solutions separated by glass walls.

To test this hypothesis, we investigated the long-range coupling between an inner NaCl solution (10 mg/L) contained in a glass vial and various outer immersion liquids, including untreated water, vibrationally treated water, and NaCl solutions. The effects of mechanical shaking and atmospheric exposure on liquid dynamics were evaluated using highresolution thermography and theoretical modeling.

We demonstrate that while mechanical shaking promotes nanobubble formation, evaporation creates internal temperature gradients that trigger Rayleigh instability and turbulent convective flows in atmospheric-exposed outer samples. Rayleigh instability in liquids induces and supports oscillations of nanobubbles, which cause wave emission. Thermographic and theoretical analysis confirms that these intense convective flows drive the oscillations and cause charge redistributions within the bubbles' hydration shells.

Our findings provide a possible mechanism showing how Rayleigh instability supports resonant nanobubble oscillations, suggesting that convective flows are a driver of long-range interactions in aqueous solutions.