Local phase transitions in driven colloidal suspensions

: Scacchi, A.; Brader, J. M.

Publisher: TAYLOR & FRANCIS LTD

: ABINGDON

: 2018

: Molecular Physics

: MOLECULAR PHYSICS

: MOL PHYS

: 116

: 3

: 378

: 387

: 10

: 0026-8976

: 1362-3028

DOI: https://doi.org/10.1080/00268976.2017.1393117

Using dynamical density functional theory and Brownian dynamics simulations, we investigate the influence of a driven tracer particle on the density distribution of a colloidal suspension at a thermodynamic state point close to the liquid side of the binodal. In bulk systems, we find that a localised region of the colloid-poor phase, a 'cavitation bubble', forms behind the moving tracer. The extent of the cavitation bubble is investigated as a function of both the size and velocity of the tracer. The addition of a confining boundary enables us to investigate the interaction between the local phase instability at the substrate and that at the particle surface. When both the substrate and tracer interact repulsively with the colloids we observe the formation of a colloid-poor bridge between the substrate and the tracer. When a shear flow is applied parallel to the substrate the bridge becomes distorted and, at sufficiently high shear-rates, disconnects from the substrate to form a cavitation bubble.[GRAPHICS].