The stability of magnetic soap films

Abstract

Although previous studies have shown that a magnetic field can drastically alter drainage in soap films containing particles responsive to a magnetic field, which we refer to as magnetic soap films, it is yet to be understood whether a magnetic field may be able to control the rate of drainage and film stability. Furthermore, the effect of a magnetic field on key drainage mechanisms, such as marginal regeneration, is unknown. An experimental investigation involving interferometry is conducted here to develop further understanding of the behavior of horizontal soap films containing magnetite nanoparticles. Three scenarios are considered: soap films, magnetic soap films, and magnetic soap films in an inhomogeneous magnetic field. In each of the three scenarios, high-resolution images capturing the time evolution of each film are acquired, and the lifetime of each film is measured. In addition, a measure of the rate of drainage and the velocities of thin patches of fluid arising from marginal regeneration are evaluated. The results suggest that a magnetic field may be able to have either a stabilizing or destabilizing effect on magnetic soap films, depending on their composition. Furthermore, applying a magnetic field to magnetic soap films alters the trajectory of thin patches of fluid arising from marginal regeneration. This study reveals how a magnetic field can be used in conjunction with magnetic particles to control the stability of soap films, which opens up the possibility for new technologies that require a fine control of film stability.

Spontaneous Particle Ordering, Sorting, and Assembly on Soap Films

“…15 This feature makes it theoretically challenging to observe the regular particle behavior in soap films. Previous studies mostly involved passive methods, such as magnetic 16 and electrokinetic, 17 to regulate the dynamics of micro/nanoparticles within soap films. However, these studies primarily concentrated on clusters of disordered particles over the whole soap film, lacking regularity and distinctive features.…”