Soap films controlled with magnetic fields

From the moment a soap film is born, it starts thinning. This thinning results in a less stable film. Reducing thinning and increasing stability could make soap films applicable for targeted release of substances or removal of contaminants, such as in carbon-free hydrogen-based energy systems, in-situ carbon capture, and drug delivery.

Research has shown that magnetic nanoparticles in soap films can affect film drainage, but their effects on film stability are unknown. Lalli et al. studied the effects of magnetic fields on soap films containing magnetite nanoparticles.

Investigating three types of soap films made with water, surfactant, glycerol and ferrofluid, the researchers captured high-resolution videos featuring interference colors arising from white-light illumination to monitor film drainage. They showed how applied magnetic fields affected the thinning rates, and determined that these fields can have both stabilizing and destabilizing effects.

“It was exciting to discover that applying a magnetic field does have an important impact on film stability and can have a stabilising or destabilising effect depending on the composition of the film,” said author Navraj Lalli. “We hope this study will be the catalyst for novel applications that rely on a controllable film stability.”

The authors plan to investigate the effect of time-varying magnetic fields, which could lead to an increased control over the behaviour of magnetic soap films. They also hope to study other film configurations using artificial intelligence methods to improve quantitative characterizations.

Source: “The stability of magnetic soap films,” by Navraj S. Lalli, Li Shen, Daniele Dini, and Andrea Giusti, Physics of Fluids (2023). The article can be accessed at https://doi.org/10.1063/5.0146164 .