No-slip hydrodynamic boundary condition for hydrophilic particles

We describe measurement and interpretation of the force acting on a smooth hydrophilic glass particle during rapid (1-100 mu m s(-1)) approach to, and separation from, a hydrophilic glass plate in viscous concentrated aqueous sucrose solutions (0.001 Pa s < eta < 0.090 Pa s). We find that the force is accurately described by Reynolds lubrication theory with a no-slip boundary condition, even at maximum strain rates of up to 250 000 s(-1). Compared to earlier studies of hydrodynamic forces on small particles, we reduce the uncertainty in the absolute particle-plate separation by using an evanescent-wave measurement of the separation.