Abdelhamid MAALI

• Application of atomic force microscopy to the study of the rheological properties of confined liquid.
• Hydrodynamics at the nanoscale: application of AFM to study the slip length of water on solid surfaces.
• Study the confined air flow and measurement of the slip length.

Recent Results:

• The contactless measurement of viscoelastic properties of soft PDMS layer using dynamic atomic force microscope

We have performed the contactless measurement of the viscoelastic property of polymer thin films in wide range of frequencies. The experiment was done in a liquid environment using dynamic Atomic Force Microscope (AFM) method. The nanoscale flow induced by the oscillation of the colloidal probe provides a precise hydrodynamic force acting on the soft thin film. From the measured mechanical response, we obtain the storage and loss moduli of the thin film. The experimental results are in good agreement with theoretical prediction for all the working frequencies. The result paves the way for the frequency response study of viscoelastic properties of the soft surfaces, like, nanobubbles, live cells and tissues.

• An experimental study on the role of friction in non-Brownian suspensions rheology:

We have performed a quantitative experimental validation of Lobry’s [1] model linking viscosity to friction and, in particular, shear thinning to load dependent friction coefficient. For this purpose, we have measured by using an AFM the pairwise friction coefficient of polystyrene particles, immersed in a Newtonian liquid, for different normal loads [2] . The friction coefficient obtained is then introduced into the viscosity model proposed by Lobry et al. The viscosity of suspensions consisting of these same particles dispersed in the liquid used for AFM measurements is then measured for several particle volume fractions. The very good agreement between the measured viscosity values and those predicted by the model with the coefficient of friction measured by AFM as input data [2], shows unambiguously the relevance of the scenario proposed by Lobry model [1].

[1] L. Lobry, E. Lemaire, F. Blanc, S. Gallier and F. Peters, Journal of Fluid Mechanics, ,860, 682, 2019.

[2] M. Arshad, A. Maali, C.  Claudet, L. Lobry, F. Peters, and E. Lemaire,  submitted.

• Non-contact rheology of finite-size air-water interfaces

We performed a non-contact atomic-force microscopy measurements of the hydrodynamic interactions between a rigid sphere and an air bubble in water at the micro-scale. The size of the bubble is found to have a significant effect on the response due to the long-range capillary deformation of the airliquid interface. To rationalize the experimental data, we develop a viscocapillary lubrication model accounting for the finite-size effect. The comparison between experiments and theory allows us to measure the air-liquid surface tension, without contact, paving the way towards robust non-contact tensiometry of polluted air-liquid interfaces.

• Near-field probe of thermal fluctuations of a hemispherical bubble surface:

We have performed the measurements of resonant thermal capillary oscillations of a hemispherical liquid gas interface obtained using a half bubble deposited on a solid substrate. The thermal motion of the hemispherical interface is investigated using an atomic force microscope cantilever that probes the amplitude of vibrations of this interface versus frequency.  The spectrum of such nanoscale thermal oscillations of the bubble surface presents several resonance peaks and reveals that the contact line of the hemispherical bubble is pinned on the substrate. The analysis of these peaks allows to measure the surface viscosity of the bubble interface. Minute amounts of impurities are responsible for altering the rheology of the pure water surface.

• Direct measurement of the elastohydrodynamic lift force at the nanoscale:

We have performed the first direct measurement of the elastohydrodynamic lift force acting on a sphere moving within a viscous liquid, near and along a soft substrate under nanometric confinement. Using atomic force microscopy, the lift force is probed as a function of the gap size, for various driving velocities, viscosities, and stiffnesses. The force increases as the gap is reduced and shows a saturation at small gap. The results are in excellent agreement with scaling arguments and a quantitative model developed from the soft lubrication theory, in linear elasticity, and for small compliances. For larger compliances, or equivalently for smaller confinement length scales, an empirical scaling law for the observed saturation of the lift force is given and discussed.

• Visco-elastic drag forces and crossover from no-slip to slip boundary conditions for flow near air-water interfaces:

The “free” water surface is generally prone to contamination with surface impurities be they surfactants, particles or other surface active agents. The presence of such impurities can modify flow boundary near such interfaces in a drastic manner. Here we show that vibrating a small sphere mounted on an AFM cantilever near a gas bubble immersed in water, is an excellent probe of surface contamination. Both viscous and elastic forces are exerted by an air-water interface on the vibrating sphere even when very low doses of contaminants are present. The viscous drag forces show a cross-over from no-slip to slip boundary conditions while the elastic forces show a nontrivial variation as the vibration frequency changes. We provide a simple model to rationalize these results and propose a simple way of evaluating the concentration of such surface impurities.

• Visco-capillary response of gas bubbles probed by thermal noise atomic force measurement:

Thermal noise measurements of a vibrating sphere close to micro-sized air bubbles in water with an atomic force microscope. The sphere was glued at the end of a cantilever with a resonance frequency of few kHz. The sub-Angstrom thermal motion of the micro-sphere reveals an elasto-hydrodynamic coupling between the sphere and the air-bubble. The results are in perfect agreement with a model incorporating macroscopic capillarity and fluid flow on the bubble surface with full slip boundary conditions.

Collaborations

• Prof. Bharat Bhushan,   Nanotribology Laboratory for Information Storage and MEMS/NEMS (NLIM), USA.
• Prof. Elisabeth Charlaix, LABORATOIRE INTERDISCIPLINAIRE DE PHYSIQUE (LIPhy), Grenoble.
• Prof. Stéphane COLIN, Institut Clément Ader (ICA),  Toulouse.
• Prof. Yuliang Wang, Beihang University, China.

Publications

List of my publications in Hal Archiv

Publications since 2006-2014 :

1. Z. Zhang, V. Bertin, M. Arshad, E. Raphael, T. Salez, A. Maali,  Direct measurement of the elastohydrodynamic lift force at the nanoscale, Phys. Rev. Lett. 124, 054502
2. A. Maali, R. Boisgard, H. Chraibi, Z. Zhang, H. Kellay, A. Würger, Viscoelastic drag forces and crossover from no-slip to slip boundary conditions for flow near air-water interfaces, Phys. Rev. Lett. 118, 084501
3. Y. Wang, B. Zeng, H. T. Alem, Z. Zhang, E. Charlaix, A. Maali, Viscocapillary response of gas bubbles probed by thermal noise atomic force measurement, Langmuir 2018, 34, 4, 1371–1375
4. A.Maali , T. Cohen-Bouhacina, C. Jai, , C. Hurth, R. Boisgard, , J.P. Aimé , D. Mariolle, F. Bertin, Reduction of the cantilever hydrodynamic damping near a surface by ion-beam milling, J. Appl. Phys. Vol 99, (2006) 024908
5. A.Maali , T.Cohen-Bouhacina, G. Couturier, J.P.Aimé, Oscillatory Dissipation of a Simple Confined Liquid, Phys. Rev. Lett. 96, 086105(2006).
6. A. Maali, C. Hurth, T. Cohen-Bouhacina, G. Couturier, J.P.Aimé, Improved acoustic excitation of atomic force microscope cantilevers in liquids, Appl.Phys.Lett. 88, 163504 (2006).
7. A. Maali, T. Cohen-Bouhacina, “Maali and Cohen-Bouhacina Reply”:, Phys. Rev. Lett. 97, 179602 (2006).
8. C. Hurth, C. Tassius, J.C. Talbot, A. Maali, C. Moskalenko, P. Minard, J.P. Aimé, F. Argoul “Enzymatic activity of immobilized yeast phosphoglycerate kinase” Biosens Bioelectron. Volume 22, Issue 11, 15 May 2007, Pages 2449-2455.
9. C. Jai, T. Cohen-Bouhacina, A. Maali « Analytical description of the motion of an acoustic-driven atomic force microscope cantilever in liquid” , Appl.Phys.Lett . 90, 113512,(2007).
10. A.Maali, T.Cohen-Bouhacina, H.Kellay, ” Measurement of the slip length of water flow on graphite surface”. Appl. Phys. Lett. 92, 053101 (2008).
11. D.Lasne,A.Maali, Y.Amarouchene, L.Cognet, B.Lounis, H.Kellay ” Velocity profiles of water flowing past solid glass surfaces using fluorescent nanoparticles and molecules as velocity probes”, Phys. Rev. Lett. 100, 214502(2008).
12. A.Maali, B.Bhushan “Slip Length Measurement of Confined Air Flow Using Dynamic Atomic Force Microscopy”, Phys. Rev. E. 78, 027302(2008).
13. A.Maali , B. Bhushan “Nanorheology and boundary slip in confined liquids using atomic force microscopy”, J. Phys. Condens. Matter. 20, 315201 (2008).
14. B. Bhushan, Y. Wang, and A. Maali “Nanobubble Imaging and Coalescence Observed Using Tapping Mode AFM and Their Viscoelastic Analysis” J. Phys: Condens. Matter. 20, 485004 (2008).
15. B. Bhushan, Y. Wang, and A. Maali “Boundary slip study on hydrophilic, hydrophobic and superhydrophobic surfaces with dynamic atomic force microscopy » Langmuir. 25, 8117 (2009).
16. B. Bhushan, Y. Wang, and A. Maali “AFM measurement of boundary slip on hydrophilic, hydrophobic and superhydrophobic surfaces” Journal of vacuum and science technology J. Vac. Sci. Technol.A27, 754 (2009).
17. A. Maali, Y. Wang, B. Bhushan “Evidence of the no-slip boundary condition of water flow between hydrophilic surfaces using atomic force microscopy” Langmuir. 25, 12002, (2009).
18. J-C Talbot, A. Dautant, A. Polidori, B. Pucci, T. Cohen-Bouhacina, A. Maali, B. Salin, D. Brèthes, J. Velours and M-F Giraud “Hydrogenated and fluorinated surfactants derived from Tris(hydroxymethyl)-acrylamidomethane allow the purification of a highly active yeast F1-F0 ATP-synthase with an enhanced stability” J. Bioenerg. Biomembr. 41, 349 (2009).
19. A. Maali, Y. Pan, B. Bhushan, and E. Charlaix  “Hydrodynamic drag-force measurement and slip length on microstructured surfaces”. Phys. Rev. E 85, 066310 (2012).
20. A. Maali and  B. Bhushan, “Measurement of slip length on superhydrophobic surfaces” Phil. Trans. R. Soc. A vol. 370 no. 1967 2304-2320 (2012)
21. I. Dufour, A. Maali, Y. Amarouchene, C. Ayela, B. Caillard, A. Darwiche, M. Guirardel, H. Kellay, E. Lemaire,  F. Mathieu, C. Pellet, D. Saya, M. Youssry, L. Nicu, and A. Colin ,“The Microcantilever: A Versatile Tool for Measuring the Rheological Properties of Complex Fluids” , Journal of Sensors Volume 2012 Article ID 719898 (2012).
22. Abdelhamid Maali and Rodolphe Boisgard ,”Precise damping and stiffness extraction in acoustic driven cantilever in liquid” Journal of Applied Physics 114, 144302 (2013)
23. Abdelhamid Maali and Bharat Bhushan, “Nanobubbles and their role in slip and Drag » J. Phys.: Condens. Matter, 25 184003 (2013)
24. Yunlu Pan, Bharat Bhushan   and Abdelhamid Maali “Slip Length Measurement of Confined Air Flow on Three Smooth Surfaces” Langmuir, 29, 4298 (2013)
25. A. Darwiche, F. Ingremeau, Y. Amarouchene, A. Maali, I. Dufour, and H. Kellay “Rheology of polymer solutions using colloidal-probe atomic force microscopy”Phys.Rev.E. 87, 062601 (2013)

Book chapters :

1. T. Cohen-Bouhacina and A. Maali « AFM Imaging in physiological environment: from biomolecules to living cells» Chapitre 5 – Volume IV « Imaging and Manipulation Techniques » of books entitled « Soft Matter: Scattering, Imaging and Manipulation », KLUWER, 2008.
2. A. Maali , T. Cohen-Bouhacina, , C. Hurth, C. Jai, R. Boisgard, , J.P. Aimé, ” Dynamic AFM in liquids: Viscous damping and applications to the study of confined liquids”. Chapiter 15- Volume XII Applied Scanning Probe Methods XII, editors B.Bhushan and H. Fuchs, Spring-Verlag Berlin Heidelberg 2009.

Curriculum vitae

Name: Maali

First Name: ABDELHAMID

Date of birth: 23-01-1970

Nationality: French.

Family situation: Married, three children.

Address: Laboratoire Onde et Matière d’Aquitaine (LOMA), CNRS UMR 5798, 351 cours de la libération, 33405 Talence Cedex

Current position : Directeur de Recherches (2eme classe) CNRS Appointments

2012 : Coordinator with Lionel Bureau of the GDR liquids at interfaces

2011 : Senior CNRS researcher (Directeur de recherches CNRS).

2009 : Habilitation (HDR Universite Bordeaux1).

1997 : CNRS researcher (Charge de Recherche au CNRS), CPMOH, Bordeaux

1993-1996 : PhD in quantum physics at l’Ecole Normale Superieure de Paris under the supervision of S. Haroche and J. M. Raimond «  Oscillations de Rabi quantiques: Test Direct de la Quantification du Champ dans une cavite. »