Near-boundary Brownian motion is a classic hydrodynamic problem of great importance in a variety of fields, from biophysics to micro-/nanofluidics. However, owing to challenges in experimental measurements of near-boundary dynamics, the effect of interfaces on Brownian motion has remained elusive. Here a computational study, using molecular dynamics simulation and a newly developed Green-Kubo relation for friction at the liquid-solid interface, unambiguously reveals that the t-3/2 long-time decay of the velocity autocorrelation function of a Brownian particle in bulk liquid is replaced by a t-5/2 decay near a boundary. A general breakdown of traditional no-slip boundary condition has been observed at short-time scales and it has been shown that this breakdown has a profound impact on the near-boundary Brownian motion. These results demonstrate the potential of Brownian motion in the nearby liquid-solid interface to be used as advanced sensing applications.
1. Li, T., Kheifets, S., Medellin, D. & Raizen, M. G. Measurement of the instantaneous velocity of a Brownian particle. _Science_ 328, 1673-1675 (2010).
2. Jeney, S., Lukic, B., Kraus, J. A., Franosch, T. & Forro, L. Anisotropic memory effects in confined colloidal diffusion. _Phys. Rev. Lett._ 100, 240604 (2008).
3. Schimdt, J.R. & Skinner, J.L. Hydrodynamic boundary conditions, the Stokes-Einstein law, and long-time tails in the Brownian limit. _J. Chem. Phys._ 119, 8062-8068 (2003).