EventRoujin Ghaffari

Dynamic, adaptive colloidal crystals far from equilibrium

Self-assembly has been the center of attention of many researchers from all branches of science. Static structures such as crystals often form through energy minimization, while dynamic ones need constant energy flow to maintain their state. Most of the studies on this topic are limited to static self-assembly, and despite its ubiquity, our comprehensions of dynamic self-assembly are still in its infancy due to lack of experimental setups that can keep the system in its dynamical state.

In 2017 a state-of-the-art dynamic self-assembly method was introduced by our group.1 Here, using this method, we studied the formation of dynamic, adaptive colloidal crystals far from equilibrium. We use femtosecond laser as an energy source to drive a quasi-2D confined colloidal system far from thermodynamic equilibrium, and for the first time, we observed the formation of a rich set of dynamic adaptive colloidal crystals from pure polystyrene spheres with 500 nm diameters. We report the formation of periodic 2D Bravais lattices, Moiré patterns, honeycomb structures and aperiodic quasicrystals. Furthermore, we identify and analyze the key experimental parameters e.g., physical boundaries, and average velocity of brownian motion, affecting the formation of a variety of colloidal crystals. Our results demonstrate that highly nonlinear, strongly stochastic far from equilibrium conditions are crucial to create a variety of patterns, which are highly dynamic, and are adaptive to the changes in their environment.

We anticipate this study to be a starting point to uncover the principles of complex, dynamic adaptive systems.

AbstractRoujin_MSN 598_