Related Experiment Video
Updated: Aug 8, 2026
06:48
Single-Molecule Measurement of Protein Interaction Dynamics Within Biomolecular Condensates
Published on: January 5, 2024
Equilibrium conformational dynamics of a polymer in a solvent
James M Polson1, John P Gallant
1Department of Physics, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island, C1A 4P3, Canada. jpolson@upei.ca
The Journal of Chemical Physics
|May 20, 2006
Summary
Molecular dynamics simulations reveal polymer chain dynamics under good solvent conditions. Theoretical predictions align with simulations at high solvent densities, but discrepancies arise with decreasing density.
Area of Science:
- Polymer Physics
- Computational Chemistry
- Soft Matter Science
Background:
- Understanding polymer dynamics is crucial for materials science.
- Bead-spring models approximate polymer chains in simulations.
- Explicit solvent models capture realistic interactions.
Purpose of the Study:
- Investigate polymer chain conformational dynamics.
- Analyze the influence of chain length, solvent density, and system size.
- Compare simulation results with theoretical polymer dynamics predictions.
Main Methods:
- Employed molecular dynamics simulations.
- Utilized a bead-spring polymer model in explicit solvent.
- Analyzed time autocorrelation functions of Rouse coordinates.
Main Results:
- Observed predicted scaling gamma(p) proportional to N(-3nu) at high solvent density.
- Found theoretical predictions generally higher than measured decay rates.
- Discrepancy increased with decreasing solvent density due to Oseen approximation breakdown.
Conclusions:
- Theoretical polymer dynamics models require refinement for dilute solvent conditions.
- Improved agreement achieved by modifying theoretical expressions and using simulation-derived values.
- Finite-size scaling in simulations showed quantitative inconsistencies with theory.
More Related Videos
Related Concept Videos
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
01:59Solution Equilibrium and Saturation
Imagine adding a small amount of sugar to a glass of water, stirring until all the sugar has dissolved, and then adding a bit more. You can repeat this process until the sugar concentration of the solution reaches its natural limit, a limit determined primarily by the relative strengths of the solute-solute, solute-solvent, and solvent-solvent attractive forces. You can be certain that you have reached this limit because, no matter how long you stir the solution, undissolved sugar remains. The...
01:29The Colloidal State
The formation of a colloidal system is exemplified by an aqueous solution containing Cl− ions is introduced to another containing Ag+ ions, resulting in the precipitation of solid AgCl as extremely tiny crystals. Instead of settling out as a filterable precipitate, these crystals remain suspended in the liquid, showcasing a colloidal system.A colloidal system involves colloidal particles within the approximate range of 1 to 1000 nm in at least one dimension, dispersed in a medium called the...
02:20Dynamic Equilibrium
A reversible chemical reaction represents a chemical process that proceeds in both forward (left to right) and reverse (right to left) directions. When the rates of the forward and reverse reactions are equal, the concentrations of the reactant and product species remain constant over time and the system is at equilibrium. A special double arrow is used to emphasize the reversible nature of the reaction. The relative concentrations of reactants and products in equilibrium systems vary greatly;...
01:27Determination of Molar Masses of Polymers II
Polymer samples typically consist of macromolecular chains with a distribution of lengths, resulting in a range of molar masses rather than a single discrete value. Conventional descriptors such as the number-average molar mass and weight-average molar mass quantify this distribution but do not fully capture polymer behavior in solution..The viscosity-average molar mass provides a more realistic description of polymer behavior in solution because it accounts for the enhanced contribution of...
02:11Conformations of Cyclohexane
Cyclohexane does not exist in a planar form due to the high angle and torsional strain it would experience in the planar structure. Instead, it adopts non-planar chair and boat conformations.
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...