We report work in which an atomic force microscope (AFM) is used to stretch (and ultimately, to rupture) a thin film of liquid between a moving colloid sphere and a static plane surface. Under some circumstances, when the sphere and the surface are pulled apart sufficiently rapidly, an unexpected transient decrease in the sphere-surface separation is recorded. The results of numerical simulations of cavitation bubble dynamics suggest that the growth of a cavitation bubble within a liquid may result in the development of sufficiently large negative pressures to account for this phenomenon. The results of separate experiments, which involve acoustic pulse propagation within metre-long columns of liquid and high-speed microphotography (using a novel optical system designed for this work), are used to show that the peak tensile forces recorded in the AFM experiments correspond to the development of tensile stresses that are commensurate with the fluid's effective tensile strength (or 'cavitation threshold'). The results of this study, which, to the best of our knowledge, is the first to apply the AFM in cavitation bubble dynamics work, provide evidence that, in the cavitation of liquids within confined spaces, the growth of a cavity may be more damaging than its subsequent collapse.
|Number of pages||24|
|Journal||Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences|
|Publication status||Published - 8 Nov 2003|
- Atomic force microscope
- Fluid films
ASJC Scopus subject areas