skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Particle Dynamics in Polymer-Metal Nanocomposite Thin Films on Nanometer-Length Scales

Abstract

X-ray photon correlation spectroscopy was used in conjunction with resonance-enhanced grazing-incidence small-angle x-ray scattering to probe slow particle dynamics and kinetics in gold/polystyrene nanocomposite thin films. Such enhanced coherent scattering enables, for the first time, measurement of the particle dynamics at wave vectors up to {approx}1 nm{sup -1} (or a few nanometers spatially) in a disordered system, well in the regime where entanglement, confinement, and particle interaction dominate the dynamics and kinetics. Measurements of the intermediate structure factor f(q,t) indicate that the particle dynamics differ from Stokes-Einstein Brownian motion and are explained in terms of viscoelastic effects and interparticle interactions.

Authors:
; ; ;  [1];  [1];  [2]
  1. Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20951346
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 18; Other Information: DOI: 10.1103/PhysRevLett.98.185506; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BROWNIAN MOVEMENT; COMPOSITE MATERIALS; GOLD; INTERMEDIATE STRUCTURE; NANOSTRUCTURES; PARTICLE INTERACTIONS; POLYSTYRENE; QUANTUM ENTANGLEMENT; SMALL ANGLE SCATTERING; SPECTROSCOPY; THIN FILMS; TIME MEASUREMENT; X-RAY DIFFRACTION

Citation Formats

Narayanan, Suresh, Lee, Dong Ryeol, Li Xuefa, Wang Jin, Hagman, Aleta, and Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208. Particle Dynamics in Polymer-Metal Nanocomposite Thin Films on Nanometer-Length Scales. United States: N. p., 2007. Web. doi:10.1103/PHYSREVLETT.98.185506.
Narayanan, Suresh, Lee, Dong Ryeol, Li Xuefa, Wang Jin, Hagman, Aleta, & Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208. Particle Dynamics in Polymer-Metal Nanocomposite Thin Films on Nanometer-Length Scales. United States. doi:10.1103/PHYSREVLETT.98.185506.
Narayanan, Suresh, Lee, Dong Ryeol, Li Xuefa, Wang Jin, Hagman, Aleta, and Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208. Fri . "Particle Dynamics in Polymer-Metal Nanocomposite Thin Films on Nanometer-Length Scales". United States. doi:10.1103/PHYSREVLETT.98.185506.
@article{osti_20951346,
title = {Particle Dynamics in Polymer-Metal Nanocomposite Thin Films on Nanometer-Length Scales},
author = {Narayanan, Suresh and Lee, Dong Ryeol and Li Xuefa and Wang Jin and Hagman, Aleta and Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208},
abstractNote = {X-ray photon correlation spectroscopy was used in conjunction with resonance-enhanced grazing-incidence small-angle x-ray scattering to probe slow particle dynamics and kinetics in gold/polystyrene nanocomposite thin films. Such enhanced coherent scattering enables, for the first time, measurement of the particle dynamics at wave vectors up to {approx}1 nm{sup -1} (or a few nanometers spatially) in a disordered system, well in the regime where entanglement, confinement, and particle interaction dominate the dynamics and kinetics. Measurements of the intermediate structure factor f(q,t) indicate that the particle dynamics differ from Stokes-Einstein Brownian motion and are explained in terms of viscoelastic effects and interparticle interactions.},
doi = {10.1103/PHYSREVLETT.98.185506},
journal = {Physical Review Letters},
number = 18,
volume = 98,
place = {United States},
year = {Fri May 04 00:00:00 EDT 2007},
month = {Fri May 04 00:00:00 EDT 2007}
}
  • X-ray photon correlation spectroscopy was used in conjunction with resonance-enhanced grazing-incidence small-angle x-ray scattering to probe slow particle dynamics and kinetics in gold/polystyrene nanocomposite thin films. Such enhanced coherent scattering enables, for the first time, measurement of the particle dynamics at wave vectors up to {approx}1 nm-1 (or a few nanometers spatially) in a disordered system, well in the regime where entanglement, confinement, and particle interaction dominate the dynamics and kinetics. Measurements of the intermediate structure factor f(q,t) indicate that the particle dynamics differ from Stokes-Einstein Brownian motion and are explained in terms of viscoelastic effects and interparticle interactions.
  • Incorporating nanoparticles (NPs) within a polymer host to create polymer nanocomposites (PNCs) while having the effect of increasing the functionality (e.g., sensing, energy conversion) of these materials influences other properties. One challenge is to understand the effects of nanoparticles on the viscosity of nanoscale thick polymer films. A new mechanism that contributes to an enhancement of the viscosity of nanoscale thick polymer/nanoparticle films is identified. We show that while the viscosities of neat homopolymer poly(2-vinylpyridine) (P2VP) films as thin as 50 nm remained the same as the bulk, polymer/nanoparticle films containing P2VP brush-coated gold NPs, spaced 50 nm apart, exhibitedmore » unprecedented increases in viscosities of over an order of magnitude. For thicker films or more widely separated NPs, the chain dynamics and viscosities were comparable to the bulk values. These results - NP proximities and suppression of their dynamics - suggest a new mechanism by which the viscosities of polymeric liquids could be controlled for nanoscale applications.« less
  • Incorporating nanoparticles (NPs) within a polymer host to create polymer nanocomposites (PNCs) while having the effect of increasing the functionality (e.g.: sensing, energy conversion) of these materials, introduces additional complications with regard to the processing-morphology-function behavior. A primary challenge is to understand and control the viscosity of a PNC with decreasing film thickness confinement for nanoscale applications. Using a combination of X-ray photon correlation spectroscopy (XPCS) and X-ray standing wave based resonance enhanced XPCS to study the dynamics of neat poly-2-vinyl pyridine (P2VP) chains and the nanoparticle dynamics, respectively, we identified a new mechanism that dictates the viscosity of PNCmore » films in the nanoscale regime. We show that while the viscosities of neat P2VP films as thin as 50 nm remained the same as the bulk, PNC films containing P2VP brush-coated gold NPs, spaced 50 nm apart, exhibited unprecedented increases in viscosities of over an order of magnitude. For thicker films or more widely separated NPs, the chain dynamics and viscosities were equal to the bulk values. These results -NP proximities and suppression of their dynamics -suggest a new mechanism by which the viscosities of polymeric liquids could be controlled for 2D and 3D nanoscale applications.« less
  • No abstract prepared.
  • Nanocomposite thin films were prepared with polyurethane as a matrix and organically modified clay as a filler. The interfacial interaction between the exfoliated clay nanoplatelets and the polymeric chains has been investigated by using Atomic Force Microscopy (AFM). The nanoclay platelets show a preferential association with the hard domains of polyurethane matrix on the surface of the thin films. The pendant hydroxyl group on the nanoplatelets attract the isocyanate of the polyisocyanate and a urethane group is formed. This leads to the 'clouding' and 'entwining' of the nanoplatelets by the hard segmental chains. This is the first visual evidence ofmore » nanomaterial filler and polymer matrix interaction and it could open up a spectrum of novel property achievements in nanocomposite thin films. Also the understanding of this interaction can lead to more controlled architecture of nanocomposites.« less