Related Experiment Video
Updated: Jun 3, 2026
06:55
Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level
Published on: September 26, 2016
Modifying fragility and collective motion in polymer melts with nanoparticles
Francis W Starr1, Jack F Douglas
1Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA.
Physical Review Letters
|April 8, 2011
Summary
Nanoparticles significantly alter polymer melt fragility and molecular motion, impacting cooperative rearranging regions. Fragility reflects the temperature dependence of this cooperativity, according to Adam-Gibbs theory.
Area of Science:
- Polymer Science
- Materials Science
- Computational Chemistry
Background:
- Glass-forming polymer melts exhibit complex molecular dynamics.
- Nanoparticles (NP) can influence polymer properties.
- Understanding molecular cooperativity is key to glass transition physics.
Purpose of the Study:
- To investigate the impact of nanoparticles on polymer melt fragility.
- To analyze the effect of NP on cooperative stringlike motion.
- To connect these phenomena using the Adam-Gibbs theory.
Main Methods:
- Molecular dynamics simulations of a model glass-forming polymer melt.
- Introduction of nanoparticles with varying NP-polymer interactions and concentrations.
- Analysis of stringlike motion and fragility metrics.
Main Results:
- Nanoparticles significantly change polymer melt fragility.
- The average length of cooperative stringlike motion is altered by NP presence.
- Observed effects are dependent on NP-polymer interaction strength and NP concentration.
Conclusions:
- Fragility in polymer melts is fundamentally linked to the temperature dependence of molecular motion cooperativity.
- Stringlike motion provides a direct measure of cooperatively rearranging regions.
- Nanoparticles serve as effective modifiers of polymer melt dynamics.
Related Concept Videos
01:21Polymer Classification: Crystallinity
Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
01:34Fluid Mosaic Model
The fluid mosaic model was first proposed as a visual representation of research observations. The model comprises the composition and dynamics of membranes and serves as a foundation for future membrane-related studies. The model depicts the structure of the plasma membrane with a variety of components, which include phospholipids, proteins, and carbohydrates. These integral molecules are loosely bound, defining the cell’s border and providing fluidity for optimal function.LipidsThe most...