Microscopy movies used for Electric field driven dynamic assembly of active colloidal aggregates

Monodisperse silica particles (4 μm and 2 μm diameter, Polysciences Inc.) were used in all experiments. Fresh stock solutions of para-benzoquinone (p-BQ, 99.5%, Sigma Aldrich) and potassium chloride (KCl, Sigma Aldrich) were prepared prior to each experiment in 18.2 MΩ deionized water and used immediately. Samples were prepared in an electrolyte solution of 1 mM KCl, with BQ added to reach a final concentration of 10 mM. A liquid cell was created by placing two indium tin oxide (ITO) coated glass slides together with a non-conducting spacer of ~ 300 µm thickness between them. An external electric field was applied using a Keysight Trueform function generator. Particle dynamics were observed with a Zeiss Axio Observer 7 inverted microscope operating in bright field imaging mode. Colloids were subjected to ‘multimode’ electric potentials consisting of a 400 Hz sinusoidal oscillatory potential superimposed with a steady offset potential.