title: Centrifugal Field-Induced Colloidal Assembly: From Chaos to Order.
abstract: Given a certain binary phase, its crystal structure can usually be rationalized by thermodynamics and packing rules. However, there is still no fundamental understanding of how metastable solids form and how this is influenced by kinetic factors. Furthermore, the very early stages of crystallization remain vague. We present an experimental study using a binary mixture of colloidal particles as a model. Particle assembly is provoked by centrifugation, and the degree of separation can be adjusted precisely. Between the scenarios of random mixture (glassy state) and complete phase separation, conditions could be realized to facilitate the occurrence of various periodic structures in a single experiment. Some of these structures can only be explained by a dynamic, nonequilibrium and dissipative state. Eventually, the formation of certain metastable lattices can be interpreted as an emergent, systemic phenomenon. Thus, centrifugation can be used for studying the chaos-order transition in complex particle systems.
authors.affiliation: Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany.
authors.forename: Mengdi
authors.initials: M
authors.lastname: Chen
authors.affiliation: Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Cölfen
authors.affiliation: Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Polarz
keywords: analytical ultracentrifugation; colloidal model systems; nonclassical nucleation; self-assembly; systems phenomena