Near-wall nanovelocimetry based on Total Internal Reflection Fluorescence with continuous tracking

Abstract

The goal of this work is to make progress in the domain of near-wall velocimetry. The technique we use is based on the tracking of nanoparticles in an evanescent field, close to a wall, a technique called TIRF (Total Internal Reflection Fluorescence)-based velocimetry. At variance with the methods developed in the literature, we permanently keep track of the light emitted by each particle during the time the measurements of their positions ('altitudes') and speeds are performed. By performing the Langevin simulation, we quantified effect of biases such as Brownian motion, heterogeneities induced by the walls, statistical biases, photo bleaching, polydispersivity and limited depth of field. Using this method, we obtained slip length on hydrophilic surfaces of 1$\pm$5 nm for sucrose solution, and 9$\pm$10 nm for water; On hydrophobic surface, 32$\pm$5 nm for sucrose solution, and 55$\pm$9 nm for water. The errors (based on 95% confidence intervals) are significantly smaller than the state-of-the-art, but more importantly, the method demonstrates for the first time a capacity to measure slippage with a satisfactory accuracy, while providing a local information on the flow structure with a nanometric resolution. Our study confirms the discrepancy already pointed out in the literature between numerical and experimental slip length estimates. With the progress conveyed by the present work, TIRF based technique with continuous tracking can be considered as a quantitative method for investigating flow properties close to walls, providing both global and local information on the flow.

arXiv comment24 pages, 13 figures

References in corpus (4)

• Nanofluidics, from bulk to interfaces
• Probing the nanohydrodynamics at liquid-solid interfaces using thermal motion
• Direct measurements of hydrophobic slippage using double-focus fluorescence cross-correlation
• Multiple dynamic regimes in concentrated microgel systems

Cited by in corpus (7)

• Non-Gaussian diffusion near surfaces
• The measurement of Navier slip on individual nanoparticles in liquid
• Adsorption-Induced Slip Inhibition for Polymer Melts on Ideal Substrates
• Time dependence of advection-diffusion coupling for nanoparticle ensembles
• Near-Wall Dynamics of Concentrated Hard-Sphere Suspensions: Comparison of Evanescent Wave DLS Experiments, Virial Approximation and Simulations
• The stress tensor of dilute active colloidal suspensions
• The non-equilibrium thermodynamics of active suspensions