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Abstract The wetting effect and related applications of nanodroplets have attracted extensive research interest. In this work, we report molecular dynamics simulations of the confinement dynamics of nanodroplets at different droplet-surface interactions, surface separations, and ion concentrations under the electric field. The results show that in the case of a single droplet, there is a critical value of surface wettability for the shape transition of the confined droplet. Below this value, the droplet shrinks into a spherical shape and attaches to the surface. Above this value, the droplet splits into two smaller droplets which locate at the bottom and top surfaces, respectively. For the two-droplet cases, a liquid bridge forms and some ions migrate into the pure water droplet under the electric field. The results reveal that the ion concentration has a significant effect on the shape evolution of droplets. The stable morphology of droplets under the electric field depends on the droplet-surface interactions as well as the ion concentration. We explore the underlying mechanisms causing the morphological transition by analyzing the intermolecular interactions and interfacial characteristics. [ABSTRACT FROM AUTHOR]

A hybrid particle–continuum method is used to study the shear flow confined between two opposing walls, one of which is coated with polymer chains. Molecular dynamics (MD) is used in the particle region near the brush and Navier–Stokes (NS) equations are applied in the remaining region where the continuum assumption holds. The information exchange from the continuum region to the particle region is implemented using the constrained particle dynamics. Both Couette shear flow and oscillatory flow are considered in the present work. The effect of the shear flow on the conformational characteristics of polymer brushes is analyzed. In the overlap region, the velocities obtained from MD simulations are smoothly connected with those from NS equations. Our investigations demonstrate that the hybrid particle–continuum model is valid in exploring the shear behavior of polymer brushes. [ABSTRACT FROM AUTHOR]