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Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level
Published on: September 26, 2016
Cyclic motion of a grafted polymer under shear flow
1Departamento de Ciencias y Técnicas Fisicoquímicas, Universidad de Educación a Distancia, C/Senda del Rey, 9, Madrid 28040, Spain. rafa@ccia.uned.es
Physical Review Letters
|April 12, 2006
Summary
A flexible polymer chain tethered at one end exhibits cyclic motion in shear flow, with a distinct period related to stretching time. This motion creates long memory effects in fluids, suggesting potential resonance phenomena.
Area of Science:
- Polymer physics
- Fluid dynamics
- Computational biophysics
Background:
- End-tethered polymer chains are fundamental in biological and synthetic systems.
- Previous experiments observed cyclic motion in tethered DNA under shear flow, but a characteristic period was not clearly defined.
Purpose of the Study:
- To investigate the long-time dynamics of a single end-tethered flexible polymer chain under shear flow.
- To identify and characterize the cyclic motion and its associated time scales.
Main Methods:
- Utilized molecular dynamics (MD) and Brownian dynamics (BD) simulations.
- Analyzed the chain extension dynamics along flow and gradient directions.
Main Results:
- Confirmed cyclic motion of the polymer chain under constant shear rate.
- Revealed a well-defined characteristic period for this motion, contrary to prior suggestions.
- The primary cycling time scales with the convective stretching time, approximately 10 times the polymer's relaxation time.
Conclusions:
- The coherent, recursive motion of the polymer chain introduces significant long memory into the fluid.
- The observed dynamics suggest potential resonance effects when subjected to periodic external forcing.
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