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Polymer chain dynamics at interfaces: role of boundary conditions at solid interface.
Tapan G Desai1, Pawel Keblinski, Sanat K Kumar
1Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA. tapan.desai@inl.gov
The Journal of Chemical Physics
|February 6, 2008
Summary
We simulated polymer chains at interfaces, developing a method to reduce finite size effects. Smooth interfaces show coupled motion (Zimm dynamics), while rougher interfaces lead to independent motion (Rouse dynamics).
Area of Science:
- Polymer physics
- Interface science
- Computational chemistry
Background:
- Understanding polymer dynamics at interfaces is crucial for materials science.
- Finite size effects and hydrodynamic interactions pose challenges in simulations.
- Distinguishing between normal and transverse motion is key.
Purpose of the Study:
- To investigate the dynamical properties of a single polymer chain at a solid-liquid interface.
- To develop a correction procedure for finite size effects in simulations.
- To analyze size effects in transverse and normal directions.
Main Methods:
- Classical molecular dynamics simulations.
- Explicit solvent model.
- Development of a finite size effect correction procedure.
- Analysis of polymer and solvent motion correlations.
Main Results:
- On smooth interfaces (slip boundary), polymer and solvent motion are coupled, yielding Zimm dynamics (D ~ N(-3/4)).
- Transverse forces at the interface disrupt correlations, leading to Rouse dynamics (D ~ N(-1)).
- Distinct size effects were observed in transverse and normal directions.
Conclusions:
- The study clarifies polymer dynamics at interfaces based on interface properties.
- The developed correction method improves simulation accuracy for hydrodynamic effects.
- Results highlight the transition from Zimm to Rouse dynamics based on interfacial conditions.
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