It's Alive! Spontaneous Motion of Shear Thickening Fluids Floating on the Air-Water Interface

摘要

In this fluid dynamics video, we show the spontaneous random motion of thinfilaments of a shear-thickening colloidal dispersions floating on the surfaceof water. The fluid is a dispersion of fumed silica nanoparticles in a lowmolecular weight polypropylene glycol (PPG) solvent. No external field or forceis applied. The observed motion is driven by strong surface tension gradientsas the polypropylene glycol slowly diffuses from from the filaments into water,resulting in the observed Marangoni flow. The motion is exaggerated by the thinfilament constructs by the attractive interactions between silica nanoparticlesand the PPG.