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