The dipole potential has been linked to biological functions such as protein adsorption
and insertion into membranes [6, 7], as well as effects of anesthetics [8].
Figure 1.4: An illustration of the three membrane potentials. The transmembrane
potential (ψtr'), the surface potential (ψs) and the dipole potential (ψd)-
In order to accurately describe the electrostatics of membrane function it would be
necessary to fully characterize the potentials throughout the membrane. Such a
characterization is impeded by the complexity of the environment with its host of ions,
water molecules in an area of high dielectric anisotropy. Such a measurement is at
present complicated even for simple model membranes composed of a single lipid and
are prohibitively complicated for more biologically relevant multi-lipid systems. Indeed,
the problem of measuring electrical parameters across a few nanometers in fluid is a
complex one. Despite this complexity, the Gouy-Chapman theory, which assumes a
nondiscrete surface charge density and treats the aqueous phase as a constant dielectric