CAREER: NANO-PARTICLE SELF-ASSEMBLY OUT OF EQUILIBRIUM

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

CBET - 1554387 PI: Swan, James W. Nanoparticles can be the building blocks to make new materials provided that the nanoparticles can be made to assemble in prescribed ways. When the assembly process is driven by thermodynamics and is conducted under near-equilibrium conditions, nanoparticles can self-assemble spontaneously to form materials that have proven useful in a variety of applications. However, the restriction to near-equilibrium conditions limits the new structures that can be formed and limits their growth rates. To address this issue, this project will use time-varying magnetic fields to direct the assembly of nanoparticles under conditions far from equilibrium and not subject to thermodynamic constraints of near-equilibrium processes. The project will develop computational algorithms that can be used by scientists and engineers to explore potential routes to new nanoparticle-based structures. The project will also use results of the research to develop several novel educational tools, including simulations of fluid flow with nanoparticles and smartphone apps that are educational games to illustrate basic concepts of fluid dynamics. This project will test the hypothesis that out-of-equilibrium self-assembly processes, which are driven by non-conservative or time-varying forces, are not thermodynamically constrained. The project is motivated by recent experiments that used time-varying magnetic fields to form crystals from suspensions of paramagnetic colloids at unprecedented growth rates. The objective of the proposed research is to test this hypothesis with computational models and to develop a theoretical framework to describe the kinetics, stability and control of such out-of-equilibrium processes. Non-equilibrium statistical mechanics underpinned by large-scale stochastic simulations will be used to identify, investigate, and optimize out-of-equilibrium pathways for the growth of nanoparticle crystals. . The project will develop accelerated simulations of assembly kinetics, simulate assembly driven by time-varying interactions among nanoparticles, and develop theory to predict phase transitions owing to nanoparticle interactions.