(iii)
(iv)
(ii)
(i)
FIG. 8: (Colour online) Space-time plots are given for (left) the ﬁlm thicknesshand (right) the nanoparticle
layer height hp = hφ. The plot corresponds to the complete evolution resulting in the ring proﬁle of
Fig. 6(b). In both panels bright [dark] parts denote high [low] regions. The prominent central dark-bright
border in the left panel indicates the change of the position of the contact line in time. Over time, four
regimes can be distinguished: (i) fast motion before pinning, (ii) nearly no front motion during self-pinning,
(iii) slow motion after depinning, and (iv) ﬁnal evaporation from the center.
should also be investigated further in the simple case presented here.
IV . CONCLUSION
We have discussed recent work on pattern formation processes in ﬁlms and drops of evaporating
suspensions/solutions of polymers and particles. After reviewing experiments on suspensions of
thiol-coated gold nanoparticles in toluene we have focused on the modelling of the transport and
phase change processes involved. A theoretical approach to the modelling of the hydrodynamics
on the mesoscale has been described as well as more microscopic models for the dynamics in the
observed nanoscopic ‘postcursor’ ﬁlm. In particular, we have introduced (i) a microscopic kinetic
Monte Carlo model, (ii) a dynamical density functional theory and (iii) a hydrodynamic thin ﬁlm
model.
The kinetic Monte Carlo model and the dynamical density functional theory can both be used to
investigate and understand the formation of polygonal networks, spinodal and branched structures
resulting from the dewetting of an ultrathin ‘postcursor’ ﬁlm that remains behind the mesoscopic
dewetting front. They are, however, not capable of describing the dynamical processes in a meso-
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