Biological & Soft Matter Seminar: Engineering Entropy for Self Assembly
Prof. Sharon Glotzer, University of Michigan
Joint seminar of the Sackler Center for Computational Molecular and Materials Science and of the Biological and Soft Matter community
Ordered assemblies formed spontaneously from colloidal building blocks of nanometer to micron size are prevalent in natural, biological, and synthetic systems. These assemblies can exhibit great structural complexity, and can exhibit potentially novel and desirable properties. Two inter-related "holy grails" in the emerging discipline of assembly science and engineering are (1) the prediction of crystal and other ordered structures from knowledge of the constituent building blocks, and (2) the inverse design of the optimal building block for self assembly into a target structure. Much progress has been made on both fronts by considering "anisotropy dimensions" for building blocks that allow for the systematic study of how building block attributes dictate preferred structures. Among the many forces responsible for the formation of highly organized structures, entropy stands apart as a statistical "force" that can drive crowded systems toward order. Entropic forces are of particular importance in colloidal assembly, where they can be as large as several kT at the onset of ordering, competing with van der Waals, electrostatic, and other interactions, and can even be directional. Through new extensions of statistical thermodynamics, alchemical ensembles that sample particle attributes such as shape can provide solutions to the inverse design problem.
Seminar Organizer: Guy Yaacoby