384079 Low-Dimensional Dynamic Models of Colloidal Cluster Assembly Using Tunable Electric Fields

Thursday, November 20, 2014: 4:23 PM
Crystal Ballroom A/F (Hilton Atlanta)
Raghuram Thyagarajan1, Dimitrios Maroudas2, Michael A. Bevan3 and David Ford1, (1)Chemical Engineering, University of Massachusetts Amherst, Amherst, MA, (2)Department of Chemical Engineering, University of Massachusetts, Amherst, Amherst, MA, (3)Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD

Electric fields can be used to facilitate the assembly of small numbers (10-1000) of colloidal particles into ordered structures that may be employed as photonic crystals and other meta-materials. Control of such assembly processes in real time would be enhanced by the availability of low-dimensional dynamic models that accurately capture the particle-level physics. In this paper we describe the building of such models for a specific system: 210 silica particles of micron size in aqueous solution under the influence of a quadrupole field with adjustable voltage. We use a combination of Monte Carlo umbrella sampling and diffusion maps (DMaps) to identify the slow, low-dimensional manifolds in this system. The DMap coordinates are correlated against set of candidate order parameters (OPs) to identify a suitable choice of observables. We build Fokker-Planck (Smoluchowski) models in the chosen OPs and generate free energy and diffusivity landscapes at various voltage levels. Strategies for incorporating this information into real-time process control algorithms are also discussed.

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See more of this Session: Computational Studies of Self-Assembly
See more of this Group/Topical: Engineering Sciences and Fundamentals