Frictional forces in an electrolytic environment

We propose a theoretical description of frictional phenomena in nanoscale layers of electrolyte solutions embedded between two plates, one of which is externally driven. It is shown that the presence of nonuniform charge distributions on the plates leads to a space-dependent frictional force, which enters into the equation of motion for the top driven plate. The equation displays a rich spectrum of dynamical behaviors: periodic stick-slip, erratic, and intermittent motions, characterized by force fluctuations, and sliding above the critical velocity. Boundary lines separating different regimes of motion in a dynamical phase diagram are determined. The dependences of the frictional force and regimes of motion on an electrolyte concentration, a surface charge distribution, and a thickness of the liquid layer are predicted. The relevance to existing systems and predictions amenable to different experiments are discussed.