F. Carrique, A. Quirantes, A.V. Delgado: Dielectric
relaxation
and distribution function of relaxation times in dilute colloidal
suspensions
Coll. Surf A 97, 141-149 (1995)
ABSTRACT: This paper describes an empirical approach
to
the theoretical distribution function of relaxation times (DFRT) that
best
characterizes the dielectric behaviour of colloidal suspensions,
according
to the model proposed by DeLacey and White (E.H.B. DeLacey and L.R.
White,
J. Chem. Soc., Faraday Trans. 2, 77 (1981) 2007; DW hereafter).
It is well known that this model predicts a dielectric response that
cannot
be given in terms of a single relaxation time for the system, even if
the
colloidal particles are homogeneous spheres. Hence, the suspension must
be characterized by a distribution of relaxation times; the dielectric
response of a dilute colloidal suspension is described in this work
using
a reasonable DFRT, and the results are compared to the predictions of
the
DW model. It is demonstrated that such a DFRT is also a suitable
approximation
to the results obtained using more recent theories, incorporating into
the explanation of the dielectric properties of the suspension the
possibility
of surface conductivity in the inner part of the double layer.
Keywords: Dielectric
relaxation, distribution function
of relaxation times; dynamic Stern layer model; standard electrokinetic
model