Research project: FNRS PDR – Thermo-Magneto-Capillary Self-Assembly (FNRS PDR 31252084 (2018-2022), collaboration with Prof. Nicolas VANDEWALLE (ULg))
Controlled Thermo-Magneto-Capillary Self-Assembly
Spontaneous generation of order in systems made of numerous components, called self-assembly, is known to be ubiquitous in biology and chemistry at the molecular level. Self-assembly is also encountered across length scales (from µm to cm), offering opportunities to generate 2D and 3D elaborated structures with low cost and simplified manipulations. This scale is called the mesoscale, in between bottom-up and top-down forms of fabrication. Using capillary driven mesoscale self-assembly to create complex structures is a scientific challenge that we will address in this project, focusing in particular on particles trapped along a liquid-air interface (this reduces the viscous drag when compared with the bulk, and enables interfacial phenomena such as long range capillary interactions). Our groups at Université libre de Bruxelles (ULB) and at Université de Liège (ULg) have indeed developed complementary ways to manipulate particles along interfaces: (i) The group at ULB has developed in collaboration with FEMTO-ST in Besançon (France) a micromanipulation station to manipulate tiny objects along liquid interfaces thanks to the thermocapillary effect in a controlled fashion. (ii) The group at ULg generates magnetocapillary assemblies made of identical soft ferromagnetic particles that are suspended at water-air interface, and subjected to a uniform magnetic field generated by Helmholtz coils. This project aims to combine these magneto- and thermocapillary effects to create complex active structures floating at the water-air interface.
This work will be mostly led in the TIPs department of the Université libre de Bruxelles (Brussels, Belgium, Pierre Lambert), with yearly research stays at the FEMTO-ST Institute (Besançon, France, M. Gauthier and A. Bolopion). These labs have developed a long-term collaboration, as illustrated by a two co-supervised PhD thesis defended in 2010 (Dr Cyrille Lenders) and 2017 (Dr Ronald Terrazas).
They have complementary expertise towards the goals of this PhD.
Prof. Pierre LAMBERT has a recognised expertise in the field of surface tension effects in microsystems. Dr Michaël GAUTHIER and Dr Aude BOLOPION have developed new non-contact micromanipulation strategies (using for instance magnetic and dielectrophoretic forces fields) and control laws towards an accurate positioning of microcomponents.
The TIPs department belong to the Polytechnic School of Université libre de Bruxelles and operates the experimental platform micromilli.ulb.be, equipped with all necessary facilities for manufacturing and characterization of fluid flows at the small scale.
The FEMTO-ST Institute (Franche-Comté Electronique Mécanique Thermique et Optique - Sciences et Technologies) is a CNRS lab (UMR 6174) linked to the Université de Franche-Comté, the microtechniques engineering school (Ecole Nationale Supérieure de Mécanique et de Microtechniques), and the Université de Technologie de Belfort-Montbéliard. This environment includes cleanroom microfabrication facilities as well as a network of local manufacturing industries. FEMTO-ST includes many labs, among which AS2M (département Automatique et Systèmes MicroMécatroniques) will host the PhD student.
The candidate will be in charge of (1) further developing the thermocapillary micromanipulation station at ULB (Brussels), both by improving control strategies in collaboration with FEMTO-ST (Besançon) and by enriching it with magnetic control functions in collaboration with Prof. Vandewalle (Liège), (2) applying it to investigate fundamental scientific questions in physics of fluids related to the dynamics of thermocapillary forces, and (3) develop innovative strategies of control manipulation of thermocapillary assemblies. In particular, he will focus on the following questions: (1) how the thermocapillary effect can affect the magnetocapillary bond and impact magnetocapillary assemblies; (2) how the magnetic field can be used as a elastic restoring force to measure thermocapillary forces (nN-µN range); (3) how the thermocapillary flow can be used to correct self-assembled patterns by adding/removing particles individually; (4) how thermocapillary barriers can confine magnetocapillary swimmers; (5) how thermocapillary flow can be used to improve the swimming capability of magnetocapillary assemblies.
Figure 1 : Complementary scientific activities along two axes : thermocapillary and magnetocapillary effects. Stationnary and variable cases for fields are distinguished in order to separate static structures and dynamical phenomena. Combining effects will open new ways to manipulate particles along interfaces.
Terrazas-Mallea, R.T., Bolopion, A., Beugnot, J.-C., Lambert, P., Gauthier, M., 1D manipulation of a micrometer size particle actuated via thermocapillary convective flows, (2017) IEEE International Conference on Intelligent Robots and Systems, 2017-September, art. no. 8202187, pp. 408-413.
Muñoz, E., Quispe, J., Lambert, P., Bolopion, A., Terrazas, R., Régnier, S., Vela, E. Optimizing the speed of single infrared-laser-induced thermocapillary flows micromanipulation by using design of experiments (2017) Journal of Micro-Bio Robotics, 12 (1-4), pp. 65-72.
Terrazas-Mallea, R.T., Bolopion, A., Beugnot, J.-C., Lambert, P., Gauthier, M. Laser-Induced thermocapillary convective flows: A new approach for noncontact actuation at microscale at the fluid/gas interface (2017) IEEE/ASME Transactions on Mechatronics, 22 (2), art. no. 7782755, pp. 693-704.
We are seeking a talented and enthusiastic student to perform a PhD in microrobotics for physics of fluid. The candidate should have a strong background in control and programming (C++, Matlab, Simulink), interest for applied physics and physics of fluids. The candidate should have good command of spoken and written English. For more information regarding the PhD studies at the ULB please check the website (http://www.ulb.ac.be/rech/doctorants/index-en.html).
Applications including CV, names of two reference persons and statement of future interests should be sent to Prof. Pierre LAMBERT (email@example.com) and Dr Aude BOLOPION (firstname.lastname@example.org)
Duration: 4 years full time.
Starting date: Immediate to September 2018
Deadline for the submission of applications: Position open until filledLire la suite