Measurement of Navier Slip on Individual Nanoparticles in Liquid

The Navier slip condition describes the motion of a liquid relative to a neighboring solid surface, with its characteristic Navier slip length being a constitutive property of the solid-liquid interface. Measurement of this slip length is complicated by its small magnitude, expected to be in the nanometer range based on molecular simulations. Here, we report an experimental technique that interrogates the Navier slip length on individual nanoparticles immersed in liquid with subnanometer precision. Proof-of-principle experiments on individual, citrate-stabilized, gold nanoparticles in water give a constant slip length of 2.7 +/- 0.6 nm (95% C.I.), independent of particle size. Achieving this feature of size independence is central to any measurement of this constitutive property, which is facilitated through the use of individual particles of varying radii. This demonstration motivates studies that can now validate the wealth of existing molecular simulation data on slip.

Automated summary

The Navier slip condition describes the motion of a liquid relative to a neighboring solid surface, with its characteristic Navier slip length being a constitutive property of the solid-liquid interface. Measurement of this slip length is complicated due to its small magnitude, but experimental technique that interrogates the Navier slip length on individual nanoparticles immersed in liquid has been developed with subnanometer precision. Proof-of-principle experiments show a constant slip length of 2.7 +/- 0.6 nm (95% C.I.) on individual, citrate-stabilized, gold nanoparticles in water, independent of particle size, motivating further studies to validate existing molecular simulation data on slip.