Interfacial slip and flows in nanotubes

The question of the hydrodynamic boundary condition of fluids at solid surfaces has entertained the field of fluid transport for most than 20 years. The debate has been quite intense among experimental groups reporting strongly contrasted results. This culminated notably with the measurement of ultra-fast flows in carbon nanotube (CNT) membranes by several groups ten years ago, which pointed to considerable surface slippage and nearly frictionless transport in CNT [1].
In this presentation I will review the main physical mechanisms underlying hydrodynamic slippage, as well as the various experimental results obtained in this domain. I will in particular discuss our recent experimental efforts to measure the transport and permeability of individual nanotubes [2,3]. Our experiments reveal diameter-dependent surface slippage in carbon nanotubes, with giant flow enhancements in the smallest tubes [3]. In contrast, their boron-nitride analogues, which have the same crystalinity as CNT, but are electronically different, exhibit no slippage. This points to a hitherto not appreciated link between hydrodynamic flow and the electronic structure of the confining material.

[1] « Flows in one-dimensional and two-dimensional carbon nanochannels: Fast and curious», M. Majumder, A. Siria, L. Bocquet, MRS Bulletin, April 2017.
[2] « Giant osmotic energy conversion measured in a single transmembrane boron-nitride nanotube », A. Siria, P. Poncharal, A.-L. Biance, R. Fulcrand, X. Blase, S. Purcell, and L. Bocquet, Nature 494, 455-458 (2013).
[3] «Massive radius-dependent flow slippage in single carbon nanotubes », E. Secchi, S. Marbach, A. Niguès, D. Stein, A. Siria and L. Bocquet, Nature 537 210 (2016).