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Molecular imaging of slip in entangled DNA solution
Pouyan E Boukany1, Orin Hemminger, Shi-Qing Wang
1Nanoscale Science and Engineering Center for Affordable Nanoengineering of Polymeric Biomedical Devices, The Ohio State University, Columbus, Ohio 43210, USA.
Physical Review Letters
|September 28, 2010
Summary
This study provides the first molecular imaging of wall slip in entangled DNA solutions. It reveals that interfacial chain disentanglement causes wall slip and DNA tumbling under shear.
Area of Science:
- Polymer Physics
- Rheology
- Molecular Dynamics
Background:
- Wall slip is a critical phenomenon in polymer processing, affecting material flow and performance.
- Understanding molecular mechanisms of wall slip in entangled polymer solutions remains challenging.
Purpose of the Study:
- To achieve the first molecular imaging of wall slip in entangled polymer solutions.
- To correlate DNA molecular conformations with the magnitude of wall slip.
- To investigate the role of interfacial chain disentanglement in wall slip.
Main Methods:
- Utilized confocal fluorescence microscopy for molecular imaging.
- Employed rheometry to measure solution properties.
- Studied entangled DNA solutions under shear in the nonlinear response regime.
Main Results:
- Successfully captured molecular images of wall slip in entangled DNA solutions.
- Observed that interfacial chain disentanglement leads to wall slip beyond the stress overshoot.
- Found that significant disentanglement can induce tumbling of individual DNA molecules.
Conclusions:
- Interfacial chain disentanglement is the primary molecular mechanism driving wall slip in entangled DNA solutions.
- The study provides direct molecular evidence linking polymer conformation to macroscopic flow behavior.
- This work offers new insights into the fundamental physics of polymer solutions at interfaces.
