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Title: Anomalous chain diffusion in polymer nanocomposites for varying polymer-filler interaction strengths

Abstract

Anomalous diffusion of polymer chains in a polymer nanocomposite melt is investigated for different polymer-nanoparticle interaction strengths using stochastic molecular dynamics simulations. For spherical nanoparticles dispersed in a polymer matrix the results indicate that the chain motion exhibits three distinct regions of diffusion, the Rouse-like motion, an intermediate subdiffusive regime followed by a normal Fickian diffusion. The motion of the chain end monomers shows a scaling that can be attributed to the formation of strong 'networklike' structures, which have been seen in a variety of polymer nanocomposite systems. Irrespective of the polymer-particle interaction strengths, these three regimes seem to be present with small deviations. Further investigation on dynamic structure factor shows that the deviations simply exist due to the presence of strong enthalpic interactions between the monomers with the nanoparticles, albeit preserving the anomaly in the chain diffusion. The time-temperature superposition principle is also tested for this system and shows a striking resemblance with systems near glass transition and biological systems with molecular crowding. The universality class of the problem can be enormously important in understanding materials with strong affinity to form either a glass, a gel or networklike structures.

Authors:
 [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Center for Computational Sciences
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
979352
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Physical Review E
Additional Journal Information:
Journal Volume: 81; Journal Issue: 4
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 36 MATERIALS SCIENCE; AFFINITY; CHAINS; DIFFUSION; GLASS; MONOMERS; POLYMERS; STRUCTURE FACTORS

Citation Formats

Goswami, Monojoy, and Sumpter, Bobby G. Anomalous chain diffusion in polymer nanocomposites for varying polymer-filler interaction strengths. United States: N. p., 2010. Web. doi:10.1103/PhysRevE.81.041801.
Goswami, Monojoy, & Sumpter, Bobby G. Anomalous chain diffusion in polymer nanocomposites for varying polymer-filler interaction strengths. United States. doi:10.1103/PhysRevE.81.041801.
Goswami, Monojoy, and Sumpter, Bobby G. Fri . "Anomalous chain diffusion in polymer nanocomposites for varying polymer-filler interaction strengths". United States. doi:10.1103/PhysRevE.81.041801.
@article{osti_979352,
title = {Anomalous chain diffusion in polymer nanocomposites for varying polymer-filler interaction strengths},
author = {Goswami, Monojoy and Sumpter, Bobby G},
abstractNote = {Anomalous diffusion of polymer chains in a polymer nanocomposite melt is investigated for different polymer-nanoparticle interaction strengths using stochastic molecular dynamics simulations. For spherical nanoparticles dispersed in a polymer matrix the results indicate that the chain motion exhibits three distinct regions of diffusion, the Rouse-like motion, an intermediate subdiffusive regime followed by a normal Fickian diffusion. The motion of the chain end monomers shows a scaling that can be attributed to the formation of strong 'networklike' structures, which have been seen in a variety of polymer nanocomposite systems. Irrespective of the polymer-particle interaction strengths, these three regimes seem to be present with small deviations. Further investigation on dynamic structure factor shows that the deviations simply exist due to the presence of strong enthalpic interactions between the monomers with the nanoparticles, albeit preserving the anomaly in the chain diffusion. The time-temperature superposition principle is also tested for this system and shows a striking resemblance with systems near glass transition and biological systems with molecular crowding. The universality class of the problem can be enormously important in understanding materials with strong affinity to form either a glass, a gel or networklike structures.},
doi = {10.1103/PhysRevE.81.041801},
journal = {Physical Review E},
number = 4,
volume = 81,
place = {United States},
year = {2010},
month = {1}
}