Colloidal patchy particle architectures Simulations of accurate models in and out of equilibrium

Some material properties and functionalities arise from a collective organization mediated by non-covalent bonds between their constituent building blocks such as molecules or colloidal particles. Understanding such complex matter, specifically when these systems are out of equilibrium, remains a grand challenge.
In this thesis, we use patchy colloidal particles interacting via critical Casimir interactions that can act as mesoscopic structural analogues of molecular, supramolecular and bio-inspired architectures. These particles can make directed bonds, follow Boltzmann statistics and are directly observable via e.g. confocal microscopy. By means of simulations, we give microscopic insight into the structural behaviors and responses of colloidal matter both in and out of equilibrium.
First, we developed an accurate patchy particle potential in a hybrid bottom-up/top-down coarse-graining approach. Based on the particle’s geometry and the universal scaling theory, we benchmarked simulation outcomes onto experimental measurements of divalent patchy particles.
As an alternative to explicit simulations, Wertheim's theory predicts the thermodynamic equilibrium of these systems. In chapter 3, we adapted Wertheim’s theory to accurately predict extremely confined systems as inspired by the effect of gravity on the patchy particle distributions.
Finally, we investigated the effect of activity on the patchy particle architectures such as dimers, decamers, rings and networks. We find that the activity can enhance as well as reduce the stability of architectures, deform the intact structures, alter the mechanisms of fragmentation, and increase bond formation. In activated networks, we observe three distinct global structures upon increasing activity: a homogeneous, an inhomogeneous, and a phase separated structure.