ESPCI web site
ESPCI PARIS
Lieu de travail :
Paris - Ile-de-France - France
Intitulé du sujet :
Metal-Organic Frameworks (MOFs) - Spin Crossover Complexes (SCO) hybrid architectures for sensing applications
Champs scientifiques :
– Chimie
– Chimie
– Physique
Description :
Future micro-surgeons in aortic flows, robotic assistance or drone sea rescue under degraded conditions will lead to new applications but will also face fundamental limits : their surrounding flow perturbations usually significantly surpasses their self-propulsive forces. This represents a major problem for realizing their full potential.
Surprisingly a school of fishes or a flock of birds is often more robust to violent external perturbations than isolated individuals. It originates from their local interactions and leads to an emerging collective robustness. As a collective object, they form an ordered and cohesive structure which collectively processes the external perturbations. The development of robotic swarms is a burgeoning field which is rapidly growing. From a theoretical perspective, the modularity and programmability of the interactions between robots is fascinating and paves the way to self-learning collective phases. The interactions could be tuned autonomously and dynamically to optimize the transport properties in a noisy or disordered environment.
The goal of this PhD project is to explore numerically the properties of programmable active matter for transport optimization in degraded situations.
Part I, passive swarms. We will implement numerical swarms of self-propelled particle with passive interactions. For a fixed interaction potential, the self-propelled objects move together in a crystalline order. We will investigate the transport properties of this passive state of active matter in a noisy environment (beyond small perturbations approach). Specifically, we will examine the influence of the strengths and range of interactions into a gradient field in a violently perturbed environment We will examine to which extent collective transport surpasses the performance of an individual motion.
Part II, phase transition of dynamical swarms. When the interactions are modulated the system becomes the active counterpart of a time crystal. We expect that modulating the interactions will triggers a dynamical phase transition towards a Floquet state of active matter. In passive systems, the modulation of interactions triggers a parametric instability which can be understood as a very efficient frequency filter. We aim at leveraging this property into active systems to promote collective robustness of swarms.
Part III, self-learning swarms. The amplitude and frequency as well as the network of interactions between individuals can be tuned as wanted and even dynamically if the environment is changing. Indeed, in programmable active matter, a program can be imbedded on board of each individuals. As a result, the parameter optimization can be achieved autonomously. In that sense the assembly changes its rules of interactions collectively and “self-learns” its environment. Mimicking a reservoir computing, we will examine whether the multiple degree of freedom of the system enables an efficient convergence towards the optimum.
3i aspect of the project
During the past decade, researchers from IMAP have produced series of functional MOFs or MOFs nanoparticles in a view of potential applications in various fields (adsorption, sensing, catalysis, health…), requiring a strong crossover of expertise (chemical engineers, materials scientists, biologists, pharmacists…). This project represents another fascinating opportunity to assess the potential of MOFs in the field of sensing. It will be at the interface between synthetic chemistry, as it will involve the synthesis of coordination complexes, MOFs and hybrid solid and solid-state physics, as an important part of the project will be devoted to the characterization of the switching properties of the designed solids by a combination of magnetic measurements (performed at LPEM, ESPCI), spectroscopies (UV-Vis, luminescence, EPR…) and advanced X-Ray diffraction experiments (high-resolution PXRD, synchrotron based SCXRD, PDF…). The combination of both synthesis and advanced characterization of the solids will be a keypoint for the project. Indeed, understanding how the structure of the solids affects their switching behavior and therefore, their sensing ability, will be necessary in order to design materials with “improved” properties. This strategy based on the interplay between physics and chemistry will definitely be an asset to design materials presenting sensing properties (sensitivity, selectivity…) beyond the state of the art, which may further be integrated into real sensing devices.
Dr. Serre and Dr. Tissot have developed during the past decade a very strong international network in the fields of MOFs and their applications and of switchable solids throughout Europe or Asia. One could therefore establish here collaboration with foreign research teams expert in the study of the switching mechanism of the solids developed in the project, for example with the Physical Chemistry Department of the University of Geneva (Switzerland), expert in photophysics and photocrystallography. A possibility would be to send the PhD candidate for a research journey in the team in order to finely characterize the best materials identified through this project. At longer term, this could set the basis of a new EU H2020 project.
Nature du financement :
Financement public/privé
Précisions sur le financement :
MSCA Cofund UPtoPARIS
Présentation établissement et labo d’accueil :
ESPCI PARIS
The Hosting Lab FRE2000 Paris Porous Material Institute
The project will be performed at the Institut des Matériaux Poreux de Paris, which is a joint CNRS-ENS-ESPCI laboratory created in September 2016 that possesses a strong expertise in the design, synthesis optimization (down to the nanoscale), and shaping of Metal Organic Frameworks (MOFs) for applications ranging from separation, catalysis, energy, sensing and health. State-of-the-art world-class scientific facilities are available in the group or at the ENS and ESPCI, ideally suited to the successful development of the project. Among them, the following are outlined laboratories for organic and inorganic synthesis including Teflon lined reactors for solvothermal synthesis, batch reflux scale-up reactors, X-ray powder diffractometers for routine characterization, high throughput and high resolution analysis, PDF and temperature dependent analysis, Nitrogen porosimeters and spectroscopic facilities (UV-Vis, fluorescence, FT-IR…). A fluorimeter equipped with a vapor adsorption chamber is expected to be acquired in a near future (ESPCI).
Name of the supervisor :
Antoine Tissot
Name of the co-supervisor :
Christian Serre
Site web :
Profil du candidat :
Ideally, the candidate shall either possess a first experience both in the synthesis and characterization of materials (porous or dense) or in molecular coordination chemistry. A good sense of communication, a will to work in a multidisciplinary team, the use of office tools and a high level in English are also expected.
Date limite de candidature :
17/09/2018
> 25 et < 35 K€ brut annuel
Applications must be submitted on the UPtoPARIS website : https://www.upto.paris/
More information is available in the "How to apply" section of the website