Electrically induced reversible viscosity change in hectorite aqueous dispersion under an AC electric field

• A reversible viscosity change by AC electric field was observed.
• A reversible viscosity change occurred by electric field of a few V/mm.
• It is highly plausible that a network structure formed under the AC field.

The electrically induced viscosity change of a deionized hectorite aqueous dispersion under an alternating current (AC) electric field was investigated. The hectorite dispersion showed a reversible viscosity change when an AC electric field (< ca. 0.01 Hz) of the order of a few V/mm was applied and removed thereafter, although it showed an incomplete reversibility when a direct current (DC) electric field was applied. Regarding the mechanism of reversible viscosity change, it can be considered that the hectorite is well dispersed as individual layers or as small flocs without an electric field. These form a three-dimensional network structure, which returns to the original dispersion state upon removal of the alternating electric field.