Viscosity measurement of lubricant at uniform small gaps by combining microfluidic device and fluorescence correlation spectroscopy

Abstract

Measurement of the viscosity of the lubricant in the minute gap is important for elucidating the boundary and mixed lubrication characteristics. It has become clear that the lubricant has a specific viscosity depending on the small gap. Since the viscosity depends on the gap, measurement at a constant (uniform) gap in the measurement region was essential, but it was difficult with a gap of the order of 10 nm. In this study, we propose a method for measuring the viscosity of lubricant in a uniform small gap by combining microfluidic device and fluorescence correlation spectroscopy.