Mesoscale simulation approach for dynamics and assembly of deformable objects

In concentrated suspensions, surfactant micelles, emulsion droplets, and microgels often form contacts among the objects leading 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 type of deformation of domains also occurs in microphase separation of block copolymer systems. 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, microgels, and block copolymers. 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 balance of thermal fluctuations and deformability leads to an order-disorder transition in both cases. A unique feature of 3D materials is that multiple ordered states are possible. We have quantified their meta-stability and transitions between ordered states. These transformations are well-known in metallic systems, but have only recently been found in experiments with soft materials.