The stability of a thin liquid film supported by a double layer of spherical particles

This manuscript investigates the effect that particle hydrophobicity and packing density has on the structure and failure mode of a thin liquid film stabilised by a double layer of particles. Particle stabilised liquid films are present in many applications, from industrial separation techniques to novel materials. However, the behaviour of the particles in the film and the conditions through which they stabilise it are poorly understood. Previously published work has analysed a system in which the particles form a single layer in the film, bridging both of its sides. However, the more complicated double layer system is also of importance, especially as the criteria for film stability change. In this study, three film failure modes are identified; capillary driven failure, film inversion and particle bridging-dewetting. The conditions under which failure occur are shown to be reliant upon the distance between particles in both the same layer and the one opposite as well as the particles contact angle and the capillary pressure acting on the film. Failure capillary pressures are compared to those for a film stabilised by a single layer of particles as well as analytical models used in porosimetry.