Abstract
We review recent experiments on dewetting thin ﬁlms of evaporating colloidal nanoparticle suspensions
(nanoﬂuids) and discuss several theoretical approaches to describe the ongoing processes including coupled
transport and phase changes. These approaches range from microscopic discrete stochastic theories to
mesoscopic continuous deterministic descriptions. In particular, we focus on (i) a microscopic kinetic
Monte Carlo model, (ii) a dynamical density functional theory and (iii) a hydrodynamic thin ﬁlm model.
Models (i) and (ii) are employed to discuss the formation of polygonal networks, spinodal and branched
structures resulting from the dewetting of an ultrathin ‘postcursor ﬁlm’ that remains behind a mesoscopic
dewetting front. We highlight, in particular, the presence of a transverse instability in the evaporative
dewetting front which results in highly branched ﬁngering structures. The subtle interplay of decomposition
in the ﬁlm and contact line motion is discussed.
Finally, we discuss a simple thin ﬁlm model (iii) of the hydrodynamics on the mesoscale. We employ
coupled evolution equations for the ﬁlm thickness proﬁle and mean particle concentration. The model is
used to discuss the self-pinning and de-pinning of a contact line related to the ‘coffee-stain’ effect.
In the course of the review we discuss the advantages and limitations of the different theories, as well as
possible future developments and extensions.
The paper is published in: J. Phys.-Cond. Mat. 21, 264016 (2009),
in the V olume “Nanoﬂuids on solid substrates” and can be obtained at
http://dx.doi.org/10.1088/0953-8984/21/26/264016
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