Introduction to Electrokinetics - Electrokinetics for Petroleum and Environmental Engineers - page 5

Electrical double
layer

Slipping plane

Particle with negative
surface charge

Stern layer
-100

Diffuse layer

Suface potential
Stern potential
Zeta potential

mV

0

Distance from particle surface

Figure 1.3 Schematic representation of zeta potential ( ζ ) (after Zetasizer Nano series
technical note, Malvern Instruments).

IHP

OHP
Stern Layer Shear Plane

Solid
Surface

x sp x G

x s x i

δ

ψ s

ψ i ψ S

ψ s

ζ

ψ G

ψ ∞

x

Figure 1.4 Double layer potentials showing the Helmholtz planes and their potentials.
IHP = inner Helmholtz plane (x i ). OHP = outer Helmholtz plane (x =σ) (after Donaldson
and Alam, 2008).