  We consider the dynamic wetting and dewetting processes of films and droplets
of complex liquids on planar surfaces, focusing on the case of colloidal
suspensions, where the particle interactions can be sufficiently attractive to
cause agglomeration of the colloids within the film. This leads to an
interesting array of dynamic behaviours within the liquid and of the liquid-air
interface. Incorporating concepts from thermodynamics and using the thin-film
approximation, we construct a model consisting of a pair of coupled partial
differential equations that represent the evolution of the liquid film and the
effective colloidal height profiles. We determine the relevant phase behaviour
of the uniform system, including finding associated binodal and spinodal
curves, helping to uncover how the emerging behaviour depends on the particle
interactions. Performing a linear stability analysis of our system enables us
to identify parameter regimes where agglomerates form, which we independently
confirm through numerical simulations and continuation of steady states, to
construct bifurcation diagrams. We obtain various dynamics such as uniform
colloidal profiles in an unstable situation evolving into agglomerates and thus
elucidate the interplay between dewetting and particle aggregation in complex
liquids on surfaces.
