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http://www.complexfluids.ethz.ch/snf19 This project is supported by the Swiss National Supercomputing Centre
We investigate the dynamics of a 2D Ising model on a square lattice with conservative Kawasaki dynamics in the bulk, coupled with two external reservoirs that pull the dynamics out of equilibrium. Two different mechanisms for the action of the reservoirs are considered. In the first, called ISF, the condition of local equilibrium between reservoir and the lattice is not satisfied. The second mechanism, called detailed balance (DB), implements a DB condition, thus satisfying the local equilibrium property. We provide numerical evidence that, for a suitable choice of the temperature (i.e. below the critical temperature of the equilibrium 2D Ising model) and the reservoir magnetizations, in the long time limit the ISF model undergoes a ferromagnetic phase transition and gives rise to stationary uphill currents, namely positive spins diffuse from the reservoir with lower magnetization to the reservoir with higher magnetization. The same phenomenon does not occur for DB dynamics with properly chosen boundary conditions. Our analysis extends the results reported in Colangeli et al. [Phys. Rev. E 97, 030103(R) (2018)], shedding also light on the effect of temperature and the role of different boundary conditions for this model. These issues may be relevant in a variety of situations (e.g. mesoscopic systems) in which the violation of the local equilibrium condition produces unexpected phenomena that seem to contradict the standard laws of transport. [Colangeli, Matteo] Univ Aquila, Dipartimento Ingn & Sci Informaz Matemat, I-67100 Laquila, Italy. [Giberti, Claudio] Univ Modena & Reggio Emilia, Dipartimento Sci & Metodi Ingn, Via G Amendola 2, I-42122 Reggio Emilia, Italy. [Vernia, Cecilia] Univ Modena & Reggio Emilia, Dipartimento Sci Fis Informat & Matemat, Via G Campi 213-B, I-41125 Modena, Italy. [Kroger, Martin] Swiss Fed Inst Technol, Polymer Phys, Dept Mat, CH-8093 Zurich, Switzerland. Giberti, C (corresponding author), Univ Modena & Reggio Emilia, Dipartimento Sci & Metodi Ingn, Via G Amendola 2, I-42122 Reggio Emilia, Italy. claudio.giberti@unimore.it [hide]
Principal Investigators
Argyrios Karatrantos (PI)
Institute of Science and Technology, Luxembourg ►
Martin Kröger (PI)
Polymer Physics, ETH Zurich, Switzerland ►
Project Partners
Clement Mugemana
Institute of Science and Technology, Luxembourg ►
Jeremy Odent
Laboratory of polymeric and composite materials, Mons University, Belgium ►
Scientific Staff
Ahmad Moghimikheirabadi
Polymer Physics, ETH Zurich, Switzerland ►
Secretary
Patricia Horn
Polymer Physics, ETH Zurich, Switzerland ►
Enjoy your reading
M Kroger,
Developments in Polymer Theory and Simulation
POLYMERS English 12 (2020) 30 ►Selected conferences (co-)organized by project members
3rd Global Summit Nanotechnology & Nanomedicine
Sep 2019, 3rd Global Summit Nanotechnology & Nanomedicine, Barcelona, Spain ►
learn more ►
About this project
Fundamentally important to the processability and the material properties of polymer nanocomposites is the underlying interaction between polymer and nanoparticles, the resulting structure and dynamics. A high degree of nanoparticle dispersion is necessary for an effective reinforcement in a polymer matrix. A recent experimental approach to distributing nanoparticles into a polymer matrix is to let the interaction between nanoparticles and polymer chains to be of ionic nature.Ionic nanoparticles can impart charged polymers with unique mechanical and functional properties such as self-healing and shape memory. Upon studying a single model nanocomposite via molecular simulation, we found that nanoparticle dispersion can indeed be achieved due to the insertion of electrostatic charge, that nanoparticle diffusion slows down due to this electrostatic charge, and that the ionic nanoparticles move according to a hopping mechanism.
These recent findings have the potential to spur new studies in modelling ionic polymer nanocomposites containing ionic functionalized silica nanoparticles.
We hereby propose to focus in a more detailed and conclusive fashion on four combined experimental/theoretical research objectives:
Investigate the role of ionic interactions and calculate viscoelastic properties (viscosity, storage modulus, loss modulus) with nanoparticle loading, for differently charged and sequenced polymers.
Quantify the lifetime of dynamic crosslinks between nanoparticles and polymers, formed in ionic nanocomposites, during deformation processes.
Calculate the dynamics and structure of polymers and their entanglements for differently charged and filled polymer ionic nanocomposite models,
Resolve the role of nanosilica surface confinement on polymer entanglements and dynamics. The novelty of the proposed work stems from the combination of experiments, simulation and theoretical models to capture the interactions and polymer structural/dynamical, as well as rheological phenomena present in these ionic nanocomposites, who seem to offer qualitatively new properties worth being quantified and supplemented with an informed microscopic picture.
Lay-Summary (German only, as required by SNF)Hintergrund: Polymer-Nanokomposite (PNCs) stellen eine zunehmend wichtige Hybrid-Materialklasse dar. Das fehlende Verständnis der chemischen und physikalischen Mechanismen stellt seit Jahrzehnten ein Hindernis bei der weiteren Entwicklung dar. Für die Verarbeitung und die Eigenschaften von PNCs ist die Wechselwirkung zwischen Polymer und Nanoteilchen, sowie die resultierende Struktur und Dynamik von fundamentalem Interesse. Eine gute Dispersion der Nanoteilchen wird für die effiziente Verst&aauml;rkung von Polymer-Muttergewebe benötigt. Einer der neueren Ansätze, die diese Eigenschaft bewerkstelligen soll, ist die Verwendung von ionischen PNCs. Ionische Nanoteilchen können den ionischen Polymeren zudem neuartige mechanische und funktionelle Eigenschaften verleihen. Inhalt und Ziel des Forschungsprojekts ist ein besseres Verstädnis der ionischen PNCs. Dazu untersuchen wir die (i) Rolle von ionischen Wechselwirkungen und berechnen viskoelastische/mechanische Eigenschaften und ihre Abhäigkeit von System-Parametern (Konzentration, Ladungen, Ladungs-Sequenzen); (ii) Lebensdauer von Vernetzungspunkten in PNCs, isbesondere während Deformationsprozessen; (iii) Dynamik und Struktur der Polymere und deren Verschlaufungs-Netzwerke in Abhängigkeit der Ladungs-Sequenz; (iv) Rolle der Oberflächen-Beschaffenheit von Nano-Silikaten. Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts. Wir möchten neuen Technologien für PNCs den Weg bereiten, die benötigt werden, um leichte, hoch-qualitative, und multifunktionelle Materialien weiter zu entwickeln. Ionische PNCs verprechen nicht nur die genannten mechanischen Eigenschaften, sondern auch ein Potential für Selstheilung, ionische Leitfähigkeit, und selektive Permeabilitä Simulationsmodelle erlauben uns, die genannten Abhäigkeiten im Detail zu untersuchen, und öffnen eue Horizonte für das Design ionischer PNCs für Anwendungen etwa in der Biomedizin, Biotechnologie, Energiespeicherung, Gastrennung.
04 May 2025
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