(142a) Nanosheet Conformation Dynamics during Flow

Authors: 
Xu, Y., Texas Tech University
Green, M., Texas A&M University

We develop a general coarse-grained Brownian Dynamics (BD) methodology for simulating conformation dynamics of two-dimensional nanosheets (such as graphene, boron nitride, and metal dichalcogenides). Such nanosheets are promising materials for a variety of materials and electronics applications. Flow processing (shear, extensional) are frequently to cast liquid nanosheet dispersions and mixtures, and little has been reported in regard to the effects of such processing techniques on the shape of the nanosheets. Our BD simulations show the effects of both shear and extension on nanosheets over time. The bending moduli play a major role in these dynamics. Nanosheets with low bending moduli are prone to show a repeated coil-stretch transition under shear and an extended “washrag” conformation under elongational flow, whereas nanosheets with high moduli tend to show a tumbling response under shear and a flat extended conformation under elongational flow. Most importantly, these simulations can actually shed light on recent experimental studies of the relationship between hydrodynamic radius (measured using dynamic light scattering) and nanosheet dimensions.