Observation of Polymer Conformation Hysteresis in Extensional Flow

Highly extensible Escherichia coli DNA molecules in planar extensional flow were visualized in dilute solution by fluorescence microscopy. For a narrow range of flow strengths, the molecules were found in either a coiled or highly extended conformation, depending on the deformation history of the po...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 2003-09, Vol.301 (5639), p.1515-1519
Main Authors: Schroeder, Charles M., Babcock, Hazen P., Eric S. G. Shaqfeh, Chu, Steven
Format: Article
Language:English
Subjects:
Applied sciences
Biological and medical sciences
Biopolymers - chemistry
Chemical Phenomena
Chemistry, Physical
Computer based modeling
Computer Simulation
Deoxyribonucleic acid
DNA
DNA, Bacterial - chemistry
Energy
Equilibrium flow
Escherichia coli
Exact sciences and technology
Fluid dynamics
Fluid-dynamic forces
Fluorescence
Free energy
Fundamental and applied biological sciences. Psychology
Hydrodynamics
Hysteresis
In solution. Condensed state. Thin layers
Liquids
Materials
Microscopy, Fluorescence
Miscellaneous
Molecular biophysics
Molecules
Natural polymers
Nucleic Acid Conformation
Observation
Physico-chemical properties of biomolecules
Physicochemistry of polymers
Polymers
Relaxation time
Thermodynamics
Vapors
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Summary:Highly extensible Escherichia coli DNA molecules in planar extensional flow were visualized in dilute solution by fluorescence microscopy. For a narrow range of flow strengths, the molecules were found in either a coiled or highly extended conformation, depending on the deformation history of the polymer. This conformation hysteresis persists for many polymer relaxation times and is due to conformation-dependent hydrodynamic forces. Polymer conformational free-energy landscapes were calculated from computer simulations and show two free-energy minima for flow strengths near the coil-stretch transition. Hysteresis cycles may directly influence bulk-solution stresses and the development of stress-strain relations for dilute polymer flows.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.1086070