Crack formation in Laponite gel under AC fields

Crack formation patterns in Laponite gel are known to be strongly affected by electric fields produced by a DC (direct current) source. It can be shown that AC (alternating current) fields produce equally remarkable patterns in a radially symmetric set-up. The character of the pattern depends crucially on the field strength. A significant feature observed is the bending of radial cracks, with the curvature increasing as field strength is increased. Voltages of 20 to 70V have been applied and several features of the resulting patterns quantified. Striations on the fracture surfaces and crack speeds are also studied. •Crack formation in desiccating Laponite is studied in a radially symmetric AC field.•The crack pattern depends on the strength of the field.•The cracks tend to bend in a direction normal to the field direction.•Number of cracks and their radius of curvature vary with AC voltage.