Electroviscous effects explained

Electroviscous effects, in chemistry of colloids and surface chemistry, according to an IUPAC definition, are the effects of the particle surface charge on viscosity of a fluid.

Viscoelectric is an effect by which an electric field near a charged interface influences the structure of the surrounding fluid and affects the viscosity of the fluid.^[1]

Kinematic viscosity of a fluid, η, can be expressed as a function of electric potential gradient (electric field), $\backslash vec\; E$, by an equation in the form:

$$\backslash eta=\backslash eta\_0\; \backslash left(1+\; f\backslash ,\; \backslash lVert\; \backslash rVert^\backslash right)$$

where f is the viscoelectric coefficient of the fluid.

The value of f for water (ambient temperature) has been estimated to be (0.5–1.0) × 10⁻¹⁵ V⁻² m².^[2]

See also

• Constrictivity
• Electrorheological fluid
• Wien effect

Notes and References

1. Vincent A. Hackley, Chiara F. Ferraris, "The Use of Nomenclature in Dispersion Science and Technology", NIST Recommended Practice Guide, NIST, Special Publication 960-3, 2001.
2. Robert J. Hunter and J. V. Leyendekkers, "Viscoelectric coefficient for water", J. Chem. Soc., Faraday Trans. 1, 1978, 74, 450-455.