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A dynamical approach to dissipative self-assembly
Dr. Jason Green
Northwestern University, Department of Chemistry
|02/06/2012 - 4:00 pm - Chemical Sciences Building Room 101|
A theoretical framework is needed for chemical and physical processes far from thermodynamic equilibrium. Such a framework would drive fundamental advances in the nanoscale manipulation of matter and the synthesis of supramolecular structures. Dissipation of energy is the problematic and elusive, but ubiquitous, feature of nonequilibrium processes. Its transient and irregular nature hinders theoretical and computational developments because no microscopic detail can be discarded for systems operating out of equilibrium. This talk will focus on an approach to simplify the description of energy dissipation in nonequilibrium self-assembling systems. A model of stimuli-responsive self-assembly will be presented that mimics recent laboratory experiments of photo-switchable nanoparticles. Extensive molecular dynamics simulations of the driven self-assembly process reveal the energy transduction pathways between the assembling particles and the explicit solvent. It will be shown that a dynamical entropy can be defined for the system whose time-dependent statistics quantitatively characterize the dissipated energy. These results suggest that, as in equilibrium thermodynamics, the still-undiscovered laws governing the far from equilibrium regime may then only depend on macroscopic observables of the system. This simplified description of nonequilibrium energy transport could ultimately allow waste energy to be harnessed, leading to new synthetic routes to dynamic nanostructured materials and complex biological matter.