Title: Designing autonomous functional self-assembly in nonequilibrium.

Speaker: Avishek Das (AMOLF)

Abstract:

The synthesis of most functional materials and the operation of all biological systems occurs through self-organization away from thermal equilibrium. Designing such self-assembly rationally involves tuning the stability of target structures as well as their fluxionality. Both are difficult in nonequilibrium through conventional theoretical and numerical techniques, as particle configurations are not Boltzmann-distributed, and reaction kinetics do not obey detailed balance. I will discuss a new numerical technique we have developed for the targeted design of autonomous functional clusters in arbitrary nonequilibrium steady states, with tools from stochastic thermodynamics and optimal control theory. The algorithm solves a variational principle in the ensemble of molecular dynamics trajectories with iterative optimization steps in a design-space. We illustrate the performance by designing DNA-labeled colloids for self-assembly in a sheared steady-state, for prespecified target structures and functions. We find that far-from-equilibrium shear flow can stabilize exotic structures as well as enhance the reactive flux between colloidal states, by decoupling equilibrium trade-offs between stability and reactivity. Further, we can, through optimized design, channel the autonomous nonequilibrium force towards breaking detailed balance in any chosen reaction coordinate. Through perturbative theory, we argue that our algorithm has discovered a new design principle for how nanoscale colloidal assemblies can harvest bulk nonequilibrium forces. Hence this approach provides a general means of uncovering design principles for nonequilibrium functional materials.

This seminar will take place in room L0.06