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http://www.complexfluids.ethz.ch/snf19 This project is supported by the Swiss National Supercomputing Centre
Dendronized polymers (DPs) are large and compact main-chain linear polymers with a cylindrical shape and cross-sectional diameters of up to similar to 15 nm. They are therefore considered molecular objects, and it was of interest whether given their experimentally accessible, well-defined dimensions, the density of individual DPs could be determined. We present measurements on individual, deposited DP chains, providing molecular dimensions from scanning and transmission electron microscopy and mass-per-length values from quantitative scanning transmission electron microscopy. These results are compared with density values obtained from small-angle X-ray scattering on annealed bulk specimen and with classical envelope density measurements, obtained using hydrostatic weighing or a density gradient column. The samples investigated comprise a series of DPs with side groups of dendritic generations g = 1-8. The key findings are a very large spread of the density values over all samples and methods, and a consistent increase of densities with g over all methods. While this work highlights the advantages and limitations of the applied methods, it does not provide a conclusive answer to the question of which method(s) to use for the determination of densities of individual molecular objects. We are nevertheless confident that these first attempts to answer this challenging question will stimulate more research into this important aspect of polymer and soft matter science. [Messmer, Daniel; Yu, Hao; Kroger, Martin; Schluter, A. Dieter] Swiss Fed Inst Technol, Polymer Chem & Polymer Phys, Dept Mat, Vladimir Prelog Weg 5, CH-8093 Zurich, Switzerland. [Sanchez-Ferrer, Antoni; Mezzenga, Raffaele] Swiss Fed Inst Technol, Lab Food & Soft Mat, Dept Hlth Sci & Technol, Schmelzbergstr 9, CH-8092 Zurich, Switzerland. [Tacke, Sebastian] Swiss Fed Inst Technol, Sci Ctr Opt & Electron Microscopy, Otto Stern Weg 3, CH-8093 Zurich, Switzerland. [Nuesse, Harald; Klingauf, Juergen; Wepf, Roger] Westfalisches Wilhelms Univ Munster, Inst Medial Phys & Biophys, Robert Koch Str 31, D-48149 Munster, Germany. [Halperin, Avraham] Univ Joseph Fourier, CNRS, Lab Spectrometrie Phys, BP 87, F-38402 St Martin Dheres, France. [Tacke, Sebastian] MPI Mol Physiol, Struct Biochem, Otto Hahn Str 1, D-44227 Dortmund, Germany. [Yu, Hao] Wuhan Univ, Sch Printing & Packaging, Lab Packaging Engn, Wuhan 430000, Hubei, Peoples R China. [Wepf, Roger] Univ Queensland, Ctr Microscopy & Microanal, St Lucia, Qld 4072, Australia. Messmer, D; Schluter, AD (corresponding author), Swiss Fed Inst Technol, Polymer Chem & Polymer Phys, Dept Mat, Vladimir Prelog Weg 5, CH-8093 Zurich, Switzerland.; Mezzenga, R (corresponding author), Swiss Fed Inst Technol, Lab Food & Soft Mat, Dept Hlth Sci & Technol, Schmelzbergstr 9, CH-8092 Zurich, Switzerland.; Halperin, A (corresponding author), Univ Joseph Fourier, CNRS, Lab Spectrometrie Phys, BP 87, F-38402 St Martin Dheres, France. daniel.messmer@mat.ethz.ch; raffaele.mezzenga@hest.ethz.ch; dieter.schluter@mat.ethz.ch [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 ►
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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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