Mesoscale Simulation Approach for Dynamics and Assembly of Deformable Objects

In dilute suspensions, surfactant micelles and emulsion droplets often take spherical shapes. But at high enough concentrations, contact among the micelles or droplets leads to nonspherical shapes. In this limit, the dynamics and assembly of the suspension depend more on the interfaces between objects than the bulk objects themselves. This has similarities with foams and biological tissues in which the interfaces between deformable objects (gas bubbles or cells) play a critical role. We have adapted a mesoscale approach (called vertex models) in order to apply it to the dynamics and assembly of small deformable objects. In this way, we are developing a unifying framework to understand micelles, emulsions, and possibly small molecule metals and glasses. In this talk, we will describe the application of vertex models to small deformable objects. In particular, we have quantified the phase diagram of assembly in thin films of particles (2D simulations) and bulk assembly of particles (3D simulations). A unique feature of 3D materials is that multiple ordered states are possible. We have quantified the meta-stability of these ordered states and found a “diffusionless transformation” between ordered states. These transformations are well-known in metallic systems, but have only more recently been found in experiments with soft materials.