Detection of nanobubble generation and stability by a SOI nanophotonic ring resonator

Studies on physical aspects of nanobubbles, i.e., nanoscopic soft domains at the liquid-solid interface, have been increasingly undertaken in the past few years, see [1-3] and references therein. On the technical application side, specifically in the field of micro- and nanofluidics, it has been conjectured that nanobubbles are responsible for various phenomena associated with the liquid-solid interface, such as liquid slippage at walls, nanometer-scale anomalous attraction of hydrophobic surfaces, or the stability of colloidal systems. More fundamentally, nanobubbles are a puzzling object, i.e., the existence of nanobubbles violates classic thermodynamic laws: According to the experimental data, these bubbles have a radius of curvature smaller than 1 micron, and therefore they should dissolve on timescales of mini-seconds, due to a large Laplace pressure inside of the bubbles. In marked contrast, the experiments reveal that nanobubbles are stable for periods as long as some hours! © 2011 IEEE