laboratoire de physique statistique
 
 
laboratoire de physique statistique

Publications

Rechercher
Sophie MARBACH 


2
P U B L I C A T I O N S

S E L E C T I O N N E R
P A R M I :



 
2016
Active Osmotic Exchanger for Efficient Nanofiltration Inspired by the Kidney - Marbach, Sophie and Bocquet, Lyderic
PHYSICAL REVIEW X 6 (2016) 
LPS


Abstract : In this paper, we investigate the physical mechanisms underlying one of the most efficient filtration devices: the kidney. Building on a minimal model of the Henle loop-the central part of the kidney filtration-we investigate theoretically the detailed out-of-equilibrium fluxes in this separation process in order to obtain absolute theoretical bounds for its efficiency in terms of separation ability and energy consumption. We demonstrate that this separation process operates at a remarkably small energy cost as compared to traditional sieving processes while working at much smaller pressures. This unique energetic efficiency originates in the double-loop geometry of the nephron, which operates as an active osmotic exchanger. The principles for an artificial-kidney-inspired filtration device could be readily mimicked based on existing soft technologies to build compact and low-energy artificial dialytic devices. Such a ``kidney on a chip'' also points to new avenues for advanced water recycling, targeting, in particular, sea-water pretreatment for decontamination and hardness reduction.
Massive radius-dependent flow slippage in carbon nanotubes - Secchi, Eleonora and Marbach, Sophie and Nigues, Antoine and Stein, Derek and Siria, Alessandro and Bocquet, Lyderic
NATURE 537210-213 (2016) 
LPS


Abstract : Measurements and simulations have found that water moves through carbon nanotubes at exceptionally high rates owing to nearly frictionless interfaces(1-4). These observations have stimulated interest in nanotube-based membranes for applications including desalination, nano-filtration and energy harvesting(5-10), yet the exact mechanisms of water transport inside the nanotubes and at the water-carbon interface continue to be debated(11,12) because existing theories do not provide a satisfactory explanation for the limited number of experimental results available so far(13). This lack of experimental results arises because, even though controlled and systematic studies have explored transport through individual nanotubes(7-9,14-17), none has met the considerable technical challenge of unambiguously measuring the permeability of a single nanotube(11). Here we show that the pressure-driven flow rate through individual nanotubes can be determined with unprecedented sensitivity and without dyes from the hydrodynamics of water jets as they emerge from single nanotubes into a surrounding fluid. Our measurements reveal unexpectedly large and radius-dependent surface slippage in carbon nanotubes, and no slippage in boron nitride nanotubes that are crystallographically similar to carbon nanotubes, but electronically different. This pronounced contrast between the two systems must originate from subtle differences in the atomic-scale details of their solid-liquid interfaces, illustrating that nanofluidics is the frontier at which the continuum picture of fluid mechanics meets the atomic nature of matter.