Literatura académica sobre el tema "Propriétés de transport ionique multi-Échelles"
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Tesis sobre el tema "Propriétés de transport ionique multi-Échelles"
Pung, Hélène. "Cristaux liquides ioniques thermotropes : Relations structure/propriétés de transport ionique". Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALV007.
Texto completoDeveloping multi-scale spatial (nano/meso/micro-macroscopic) and temporal studies is crucial to understand, control, and pilot the relationships linking the structure to the ionic transport properties of hierarchically self-assembled functional materials. It is along these research lines that this exploratory work is positioned to meet their associated scientific challenges. It aims in particular to bring together elements of understanding for designing families of electrolytes with tuneable-by-design (cat/an)ionic conductivity levels and that can be implemented by reliable manufacturing processes to authorize their scalable integration into more efficient electrochemical energy conversion and storage devices. The scrutinized model families of soft-matter electrolytes are Thermotropic Ionic Liquid Crystals (TILCs), which synergistically combine dynamic hierarchical self-assembly with self-healing functionalities to encode dimensionality (quasi-1D/ quasi-2D/3D) controlled ionic transport. This research work presents and discusses the molecular engineering, syntheses and detailed studies of these model stimuli-responsive (An/Cat)ionic (A/C)-TILCs conductors.The study of the supramolecular organization of a model family of K+ and Na+ cation-conducting C-TILCs has unravelled i) a monotropic (i.e. which develops only during of the first heating scan) bicontinuous Cubic mesophase (Cubbi) with an Ia3d symmetry and ii) a hexagonal Columnar mesophase (Colhex), encoding 3D and quasi-1D transport processes, respectively. Polar ionic sub-domains are localized at the heart of the columns decorated at their periphery by aliphatic chains. The experimental study and modelling of the confinement of charge carriers within a model family of C18C18Im+/X- (X= Br-, I-, N(CN)2-) A-TILCs forming interdigitated Smectic A mesophases (SmAd are hosting quasi-2D anisotropic ionic transport) reveals a regime of nanoconfinement of anions subjected to electrostatic interactions within the ca. 1 nm-"thick" polar sub-layers within their lamellar organizations. The study of these TILCs thus addresses the functional impact of mosaicity, i.e. how the coexistence of mesomorphic domains presenting different orientations and sizes is impacting ionic transport.A first direct experimental description allows to describe the role of this dynamic mosaicity both i) on the long-range organization of mesomorphic domains and ii) onto ion transport at the meso-/macro-scopic scale. Within mesophases formed by the K+-cation conducting C-TILC, the Cubbi mesophase presents conductivity values two orders of magnitude greater than those associated to the Colhex mesophase. As the Cubbi mesophase does not require specific defect management strategies (low density of defects/homophasic interfaces), it turns out that polar subdomains can thus percolate efficiently according to an intrinsically 3D mechanism. In contrast, the long-range ordering of the (dynamic) SmAd mesomorphic domains of the C18C18Im+/N(CN)2- A-TILC, induced by the application of an external stimulus (here, a magnetic field of 1 T), results in a ca. x1.6 increase (from 92 to 145 nm) of the average size of mesomorphic domains at 80°C. Due to the reduction of the disorder and of the number of homophasic interfaces (which can penalize the transport of anions), a natural (expected) increase in conductivity values by a factor ca. x2.6 (9 to 25 µS·cm-1) is observed.Ultimately, TILCs, i.e. 2.0 electrolytic materials encoding ionic transport properties and (bioinspired) dynamic self-assembly/repairing functionalities, are consisting in an original class of stimuli-sensitive functional materials for the electrochemical conversion and storage of energy
Overton, Philip. "Electrolytes polymères monofonctionnels à conduction monocationique : synthèse et propriétés de transport d'ions lithium". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAV010/document.
Texto completoThis thesis presents "End-Capped Single-Ion Polymer Electrolytes" (EC-SIPEs) that are ionically conductive polymers having n repeating ethylene oxide (EO) units and an ionic functional group at one chain terminal. The library of EC-SIPEs presented are based on poly(ethylene oxide) mono methyl ether (mPEOn-OH) having EOn = 8, 10, 20 and 55. The anions of the electrolyte salt pair are covalently bound to the polymer as part of the end-group design. The mobility of the anion is thus limited by the low mobility of the polymer, relative to Li+. These are "Single-Ion" conductors because the majority of ionic charge transferred by Li+ cations, as demonstrated by chronoamperometry.The end-group designs target not only ionic interactions that facilitate "single-ion" conduction of Li+, but also other specific non-covalent interactions such as dipole-dipole, Van der Waals, and π-π stacking. End-groups having naphthalene (naph) and pyrene (pyr) polycyclic aromatic hydrocarbon (PAH) moieties are investigated. The functional end-groups are lithiated sulfonates (-SO3Li, -PhSO3Li), a N-naphyl sulfonamide (-SO2N(Li)Naph), and secondary N-aryl amines (-N(Li)Naph, -N(Li)Pyr). Two end-groups target specific properties: i) a "double salt" end-group has two ionic functions at one chain end, and ii) a zwitterionic EC-SIPE that conducts Li+ cations and TFSI- anions. The doubling of the number of Li+ per end-group does not correlate to an expected improvement in ionic conductivity (σ). This implies that σ is limited by the physicochemical properties of the EC-SIPE and not the Li+ concentration. The zwitterionic EC-SIPE has a high lithium transference number (t+Li= 0.8) that implies decreased mobility of the TFIS- counter-anion relative to Li+. The best overall performance is achieved by mPEOn-N(Li)Pyr (EOn= 10, 20, 55), that has σ > 1.0*10-4 S/cm at T > 40 °C, and reaches 1*10-3 S/cm at 100 °C. It exhibits constant resistivity under galvanostatic cycling (j= 10 μA.cm-2, 10*4h periods, Li|Li cell, 40 °C) and is electrochemically stable in the 0 V-3.7 V vs. Li/Li+ potential range (Li|stainless steel cell, 1.0 mV/s sweep rate, 40 °C).In Chapter I the context of the thesis is discussed through review of state-of-the-art polymer electrolytes for Li-ion batteries. These are divided into two sub-classes: i) Salt-in-Polymer (SiP) and ii) "Single-Ion" polymer electrolytes. The design of polymer electrolytes towards efficient and effective ionic conductivity is emphasized. Special attention is given to concepts for the organisation of bulk morphology for the creation of ion transport pathways that efficiently percolate through the micron length scale separating electrodes of a battery. Finally, the synthetic strategy implemented in this thesis is described.The principle results of the thesis are presented and discussed in Chapter II. A library of EC-SIPEs are characterised in terms of their electrochemical, thermal and specific ion-transport performances. Resistive features appear at high temperature and are expected to result from the aggregation of ionic end-groups. Surprisingly, the σ of EC-SIPEs having EOn= 55 improves by as much as half an order of magnitude with repeated cycling of temperature to above Tm of crystalline PEO (in the +40 °C to +100 °C range). The analysis of EC-SIPEs having different end-groups and PEO chains having EOn= 8, 10, 20, and 55 lead to the proposition of a tentative model for the percolation of ionic pathways through the EC-SIPE bulk. It is hypothesized that the ionic end-groups are localised at the grain boundaries of PEO domains. Percolation of these boundaries are proposed to be improved under appropriate, mild conditions of temperature and electromagnetic force. Finally, the synthesis methods implemented in this thesis and characterizations of EC-SIPEs are described in Chapter III
Varloteaux, Clément. "Modélisation multi-échelles des mécanismes de transport réactif : impact sur les propriétés pétrophysiques des roches lors du stockage du CO2". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00809288.
Texto completoDausse, Amélie. "Facteurs d'échelle dans la hiérarchisation des écoulements au sein d'un aquifère karstique : Analyse multi-échelles des propriétés hydrodynamiques et de transport de l'aquifère du Lez". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS073/document.
Texto completoCharacterizing groundwater flows in karst aquifers at different scales of space and time, is not an easy task due to the high level of heterogeneity of these aquifers. Because the limited testing radius of classical hydraulic methods (slug tests, pumping tests), the regional hydraulic parameters of karst systems are generally estimated using the flow recession analysis method. But this integrative method generally does not give a differentiation into regionally varying parameters. Also, it is generally difficult to gather enough data to characterize aquifer heterogeneities at regional scale. For this reason, most of studies about hydrodynamic characterization of karst aquifer focus on local scales, i.e experimental field site scale or borehole scale; measurements at small scale could then be upscaled to obtain hydrodynamic parameters at regional scale. Consequently, understanding scale dependence of groundwater flows organization in such a context is of prime importance for the development of regional scale model.In this study, the monitoring of groundwater flow and transport is performed at several scales of time and space, within a single Mediterranean karstic carbonate aquifer, the Lez karst aquifer, located South of France. Groundwater is intensely pumped in a karst conduit upstream of the main karst outlet (Lez spring), for regional water supply. At regional scale, the relatively dense groundwater monitoring network permits to determine the hydrodynamic properties of the aquifer inferred from the hydrodynamic response to pumping at the Lez spring. At the scale of the experimental field site (Terrieu site), that comprises 22 boreholes, several experiments (i.e. pumping tests, packer tests, slug and injection tests) were performed to determine the hydrodynamic properties at experimental field site scale and borehole scale. Tracer experiments were also performed to provide an estimation of transport properties both at the scale of the experimental field site and at regional scale.The hydrodynamic properties estimated at different scale of space and time (for different hydrological conditions) were compared with flow paths organization linked to the geological structure of the reservoir. At regional scale both the hydrological conditions (i.e. high or low water level) and geological compartmentalization that impact the hydraulic connectivity, control the hydrodynamic properties. Tracer experiments revealed short time transfer and high connectivity between injection points and the spring. At the experimental field site scale, pumping and tracer test highlighted heterogeneous flow pattern that can be linked to the position of boreholes and the main geological features. At borehole scale, hydraulic tests revealed a high range of hydrodynamic properties (transmissivity from 10-11 m²/s to 10-2 m²/s) depending on the investigated part of the aquifer (matrix, fracture or drain).Depending on the water level conditions, the aquifer presents variable organization of flows that modify the hydrodynamic parameters. As expected, variability of hydrodynamic parameters depends on the scale of investigation: a difference of 10 to 105 has been quantified for a same parameter characterized at borehole scale and at regional scale. This hydrogeological parameters quantification of karst system provides important constrain about multiscale modeling using conceptual models to represent the characteristics of the main flow paths
Calonne, Neige. "Physique des métamorphoses de la neige sèche : de la microstructure aux propriétés macroscopiques". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENI047/document.
Texto completoThe main objective of the thesis is to improve our knowledge about dry snow metamorphismand its physical description, at the microscopic (ice grains and pores) andmacroscopic (snow layer) scales. First, the homogenization method of multiple scaleexpansions is applied for the first time to the physics involved in dry snow metamorphism.This way, we present the equivalent macroscopic descriptions of heat and vaportransfers derived from the physical description at micro-scale. We consider at the grainscale diffusion, conduction, and forced convection, coupled to phase changes (sublimationand deposition). Second, the effective properties of transport arising in the macroscopicdescriptions (effective thermal conductivity, effective coefficient of vapor diffusion, andintrinsic permeability) are estimated from 3D images of snow spanning the whole range ofdensity and snow types. Finally, the monitoring of metamorphism with time is considered.The relationship between the microstructure and the effective properties of a snow layerare investigated during temperature gradient metamorphism using 3D images. We presentthen a new cryogenic cell that we developed to monitor the grain to grain evolution of asnow sample by time-lapse tomography during the metamorphism, and which operates atroom temperature