Dynamics of Semiflexible Colloidal Sheets in Shear Flow*

As 2D materials such as graphene, transition metal dichalcogenides, and 2D polymers become more prevalent, solution processing and colloidal-state properties are being exploited to create advanced and functional materials. However, our understanding of the fundamental behavior of 2D colloidal sheets and membranes in flow is still lacking. In this work, we perform Brownian dynamics simulations of semiflexible colloidal sheets with hydrodynamic interactions in shear flow. For athermal sheets, buckling instabilities of different mode numbers are found to vary with bending stiffness and can be understood with simple elasticity arguments. Colloidal sheets exhibit different conformational behaviors that range from seemingly chaotic towel-wringing to periodic tumbling as parameters such as bending stiffness and shear flow strength are varied.