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Molecular Entanglement and Electrospinnability of Biopolymers
Published on: September 3, 2014
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Effect of functionality on unentangled star polymers at equilibrium and under shear flow
1State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Jilin, Changchun 130022, People's Republic of China.
The Journal of Chemical Physics
|July 3, 2016
Summary
Star polymer properties change from soft and penetrable to hard and spherical with increasing functionality. Shear flow reveals shear thinning behavior dependent on functionality and shear rate.
Area of Science:
- Polymer Physics
- Soft Matter Physics
- Computational Chemistry
Background:
- Star polymers exhibit unique properties due to their branched architecture.
- Understanding their behavior under shear flow is crucial for material science applications.
Purpose of the Study:
- Investigate equilibrium and shear flow properties of star polymers.
- Analyze the influence of functionality (f) on star polymer behavior.
- Characterize shear thinning and dynamics in star polymers.
Main Methods:
- Coarse-grained molecular dynamics simulations were employed.
- Simulations covered equilibrium and shear flow conditions.
- Key properties like deformation, alignment, and dynamics were calculated.
Main Results:
- At equilibrium, star polymers transition from soft, penetrable objects to hard, spherical ones with increasing functionality.
- Arm relaxation is independent of functionality, and high-functionality stars form liquid-like structures.
- Shear flow induces changes in polymer deformation, alignment, and dynamics at a critical shear rate (γṗ).
- Shear thinning behavior is observed, with the critical shear rate decreasing as functionality increases.
- Shear thinning in high-functionality stars results from structural collapse at low shear rates and chain stretching at high shear rates.
Conclusions:
- Functionality significantly alters star polymer equilibrium properties.
- A universal critical shear rate governs shear flow behavior, independent of functionality.
- Shear thinning mechanisms differ for low and high functionality star polymers.
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