(3ez) Dynamics of Polymer Materials and Complex Fluids: Multiscale Simulations

My general research interest lies in the study of soft matter, polymer materials and complex fluid flows, using computer simulations ranging from the atomistic scale to the continuum level. Behaviors in these systems are determined by complex dynamical systems with numerous degrees of freedom, the understanding of which usually requires advanced and innovative simulation techniques and data analysis strategies. My graduate work at University of Wisconsin-Madison focused on the dynamics of non-Newtonian fluid flows. One particular project I worked on is the study of polymer-induced friction drag reduction in turbulent flows. A physical framework was proposed which consistently explains all major transitions from turbulence in Newtonian flow to that in highly viscoelastic ones. Understanding of this system could lead to the development of novel flow control strategies that greatly reduce energy consumption in fluid transportation. After moving to Massachusetts Institute of Technology as a postdoctoral associate, I started to investigate the molecular mechanism of the diffusion of small molecules in amorphous polymer matrices. Methods are being developed to systematically study and quantitatively describe the effects of polymer configurations and polymer-penetrant interactions on the movement of penetrant molecules. This insight could provide theoretical guidelines in various applications, such as solvent selection in the coating of polymer films and design of polymer membranes for liquid or gas separations. It also paves the way for the development of simulation techniques that provide better prediction of penetrant diffusivity.