2008/02/08 by A. Imperio, Alessandra Imperio, L. Reatto +2
Chemical Engineering · Materials Science · Physics and Astronomy · #Material Dynamics and Properties #Pickering emulsions and particle stabilization #Rheology and Fluid Dynamics Studies #cond-mat.soft
paper · pdf · doi:10.1103/physreve.78.021402
Submitted to Phys. Rev. E. Animations of the shear of the microphases can be found at http://pil.phys.uniroma1.it/~zapperi/Supplementaryanimations.html
arxiv created 2008/02/08 · openalex publication_date 2008/08/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the rheological properties of colloidal microphases in two dimensions simulating a model of colloidal particles with competing interactions. Due to the competition between short-range attraction and long-range repulsion, as a function of the density the model exhibits a variety of microphases such as clusters, stripes, or crystals with bubbles. We prepare the system in a confined microphase employing Monte Carlo simulations and then shear the resulting configurations by applying a drag force profile. We integrate numerically the equation of motion for the particles and analyze the dynamics as a function of the density and the applied strain rate. We measure the stress-strain curves and characterize the yielding of the colloidal microphases. The results depend on the type of microphase. (i) Clusters are easily sheared along layers and the relative motion is assisted by rotations. (ii) Stripes shear easily when they are parallel to the flow and tend to jam when they are perpendicular to it. Under a sufficiently strong shear rate perpendicular stripes orient in the flow direction. (iii) Crystals with bubbles yield by fracturing along the bubbles and eventually forming stripes. We discuss the role of dislocations, emitted by the bubbles, in the yielding process. Finally, we analyze the effect of thermal fluctuations on the rheological properties.