ESPCI web site
Le séminaire hebdomadaire du laboratoire PMMH a lieu tous les vendredis à 11h, au premier étage Barre Cassan, campus Jussieu (plan).
Stéphane Perrard
Etienne Reyssat
Virgile Thiévenaz
PMMH
BARRE CASSAN
BAT A 1ER ETAGE CASE 18
7 QUAI SAINT BERNARD
75005 PARIS
France
Tel : (33) 1 40 79 45 22
Séminaire PMMH - Lucio Isa (ETH, Zurich)
Breaking the symmetry : Designing colloidal motors and swimming at oil-water interfaces
Breaking symmetry is at the very core of achieving propulsion at the microscale, where viscous forces dominate. Nature has perfected a range of different strategies to reach this goal for swimming microorganisms, which scientists have taken inspiration from to produce artificial micro-swimmers [1]. A common way to achieve propulsion at the colloidal scale is to produce artificial particles that have asymmetric shapes and surface properties. I will first start by describing recent work in our group where we take well-known microswimmers that are propelled by self-generated asymmetrical chemical gradients (Janus swimmers) and we confine their motion at an oil-water interface. Two-dimensional confinement and interactions with the fluid interface strongly affect the propulsion speed and the directionality of the particle trajectories [2]. Furthermore, we study how the swimmers interact with complex environments constituted by self-assembled arrays of passive obstacles [3]. Moving further on from these simple swimmers, we developed a new fabrication strategy to create microswimmers with full control on their geometrical and compositional asymmetry. The method is based on the sequential deposition of microspheres on topographical templates, where we independently define the swimmers' shape by defining the shape of template, and we program their composition by fixing the deposition sequence [4]. I will show how we can use this fabrication strategy to design and obtain particles that translate, rotate, switch between these two modes of motion and even perform drag-and-drop tasks in crowded environments, propelled by uniform AC electric fields [5]. These results show how the design of microswimmers can enable the development of active components for the realization of autonomous systems working in complex environments.
References
[1] C Bechinger, R Di Leonardo, H Löwen, C Reichhardt, G Volpe, and G Volpe, Rev. Mod. Phys. 88, 045006, 2016
[2] K Dietrich, D Renggli, M Zanini, G Volpe, I Buttinoni and L Isa, New Journal of Physics, 19, 065008, 2017
[3] K Dietrich, I Buttinoni, G Volpe and L Isa, Phys. Rev. Lett. 120, 268004, 2018
[4] S Ni, J Leemann, I Buttinoni, L Isa and H Wolf, Science Advances, 2(4), e1501779, 2016
[5] S Ni, E Marini, I Buttinoni, H Wolf and L Isa, Soft Matter, 13, pp. 4252 - 4259, 2017
Séminaires (4)
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Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…) -
Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…) -
Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…) -
Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…)
Instructions générales pour les conférenciers
Le public du séminaire est très hétérogène (rien qu’au PMMH nous travaillons sur des thématiques très diverses, mécanique des fluides, des milieux granulaires, des solides, physique statistique, physique du mouillage, micro-fluidique, biophysique,...) l’objectif est donc de ne pas faire un séminaire trop spécialiste : au moins la première moitié du séminaire à un niveau accessible pour celui qui ne connaît rien sur le sujet.
Le séminaire a lieu à 11h. rendez-vous 15 minutes avant pour installer et tester la projection.
Le séminaire dure environ 45 minutes pour laisser un peu de temps pour discuter à la fin.
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