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Diffusion at functional surfaces

Applicant Jeney Sylvia
Number 143703
Funding scheme Project funding
Research institution Laboratoire de nanostructures et nouveaux matériaux électroniques EPFL - SB - IPMC - LNNME
Institution of higher education EPF Lausanne - EPFL
Main discipline Fluid Dynamics
Start/End 01.05.2013 - 31.07.2015
Approved amount 230'670.00
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Keywords (9)

Diffusion; Thermal fluctuations; Hydrodynamic vortex; Superhydrophobicity; Slip-length; Atomic force microscopy; Brownian sphere; Optical trapping; Nanostructured surfaces

Lay Summary (French)

Lead
Inspiré par l'effet lotus, le développement de surfaces auto-nettoyantes ou présentant d’autres fonctionnalités, par exemple biomimétiques, a été le sujet d'intenses recherches dans les dernières décennies. Des revêtements intelligents sont désormais systématiquement conçus à l'échelle nano et micro, entre autre, par auto-assemblage supramoléculaire de patchs hydrophobes et hydrophiles.
Lay summary

Contenu et objectifs du travail de recherche: Pour la caractérisation de l’interaction entre un liquide et son substrat, des méthodes généralement macroscopiques sont utilisées, telles que la mesure d'angle de contact d'une goutte d'eau. Avec l’essor de la micro-et nanofluidique, de nouvelles techniques de mesures multidimensionnelles et à l'échelle nanométrique de la dynamique des fluides à l'interface solide/liquide deviennent nécessaires. Cependant, jusqu'à présent, seules quelques expériences permettent des études quantitatives dans une direction soit parallèle, soit perpendiculaire à la surface avec une résolution spatiale et temporelle suffisantes. Dans ce projet, nous souhaitons développer des protocoles expérimentaux pour caractériser systématiquement différents types de surfaces fonctionnelles, allant de surfaces nanostructurées à des surfaces de cellules vivantes. Récemment, nous avons démontré qu’en observant très localement la diffusion d'une sphère immergée dans un fluide, à une distance donnée d'une surface, peut donner des informations sur les propriétés de cette surface. L'approche proposée exploite les turbulences hydrodynamiques qui se propagent entre la sphère et la surface et qui dépendent des conditions de bord et donc de la nature de la surface.

Contexte scientifique et social du projet de recherche: Notre travail génèrera des informations inédites et essentielles sur les effets de propriétés de surface, ainsi que sur les mécanismes de diffusion physico-chimiques et biologiques dans des géométries confinées. Ceci permettra de conseiller le monde industriel dans le design de surfaces et structures intelligentes.

 

Direct link to Lay Summary Last update: 20.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Calibration of optical tweezers with non-spherical probes via high-resolution detection of Brownian motion
Butykai Adam, Mor Flavio M., Gaal Richard, Dominguez-Garcia Pablo, Forró László, Jeney Sylvia (2015), Calibration of optical tweezers with non-spherical probes via high-resolution detection of Brownian motion, in Computer Physics Communications, 196, 599-610.
Selective transport control on molecular velcro made from intrinsically disordered proteins.
Schleicher Kai D., Dettmer Simon L., Kapinos Larisa E., Pagliara Stefano, Keyser Ulrich F., Jeney Sylvia, Lim Roderick Y. H. (2014), Selective transport control on molecular velcro made from intrinsically disordered proteins., in Nature Nanotechnology, 9, 525-530.
Upconversion particle as a local luminescent Brownian probe: A Photonic Force Microscopy Study
Mor Flavio M., Sienkiewicz Andrzej, Forró László, Jeney Sylvia (2014), Upconversion particle as a local luminescent Brownian probe: A Photonic Force Microscopy Study, in ACS Photonics, 1, 1251-1257.
Single potassium niobate nano/microsized particles as local mechano-optical Brownian probes
Mor Flavio M., Sienkiewicz Andrzej, Magrez Arnaud, Forró László, Jeney Sylvia, Single potassium niobate nano/microsized particles as local mechano-optical Brownian probes, in Nanoscale.

Collaboration

Group / person Country
Types of collaboration
Prof. Francesco Stellacci, EPFL Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results

Associated projects

Number Title Start Funding scheme
121396 Multidimensional Optical Force NanoSpectroscope 01.06.2009 R'EQUIP
113529 Brownian Motion in confined geometries 01.10.2006 Project funding

Abstract

Inspired by the lotus effect, the development of self-cleaning and other functional surfaces with tunable and/or biomimetic properties has attracted intense research interest in the last decades. Smart coatings are now routinely engineered, in particular by supramolecular self-assembly of hydrophobic and hydrophilic patches on a nano- and micro scale. For characterization of liquid-substrate interactions, typically macroscopic methods are used, such as contact angle measurements of a water droplet. At microscopic scale, fluid flow can be observed by different microscopy techniques and computer simulations. It could be shown that fluid flow is mainly affected by the slip-length at the solid/liquid interface, which is defined as an extrapolated distance relative to the wall where the tangential velocity component vanishes. With the advent of micro- and nanofluidics, multidimensional measurements of fluid dynamics at the solid/liquid interface down to the nano-scale have become a necessity. However, up to now only few experiments and theoretical predictions allow for quantitative studies in directions parallel and perpendicular to the surface with high enough spatial and temporal resolution. Recently, we and another group of researchers proposed that, by observing, very locally and at shortest time, Brownian motion of a sphere immersed in a fluid at a given distance from a surface could give information on surface properties. The suggested approach exploits the firstly observed effects of the hydrodynamic vortex intrinsically propagating around the Brownian sphere and reflecting at the surface. As a result, anisotropic long-time correlations in the sphere’s Brownian fluctuations can be detected in the direction parallel and perpendicular to the wall. According to latest theoretical predictions, these correlations should depend on boundary conditions at both surfaces, and be a measure for slip-length. Surprisingly, the hydrodynamic backflow carries detectable information on the characteristics of the wall over distances as long as 10 times the sphere’s radius R.In this project, we would like to develop experimental protocols to systematically characterize various kinds of surfaces, ranging from nanostructured surfaces to living cells. We should be able to gain information on short- and long-ranged effects of surface properties, and provide new insights in biological as well as physico-chemical diffusion mechanisms in confined geometries.
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