Elastic behavior of ring polymer chains

2004 ◽  
Vol 43 (2) ◽  
pp. 223-232 ◽  
Author(s):  
Yu Shen ◽  
Linxi Zhang
Keyword(s):  
Polymer Chains ◽  
Elastic Behavior ◽  
Ring Polymer

scholarly journals Investigation of Ring and Star Polymers in Confined Geometries: Theory and Simulations

Entropy ◽  
2021 ◽  
Vol 23 (2) ◽  
pp. 242
Author(s):  
Joanna Halun ◽  
Pawel Karbowniczek ◽  
Piotr Kuterba ◽  
Zoriana Danel
Keyword(s):  
Star Polymers ◽  
Polymer Chains ◽  
The Other ◽  
Nano Particles ◽  
Dilute Solution ◽  
Confined Geometries ◽  
Density Profiles ◽  
Ideal Ring ◽  
Ring Polymer ◽  
Monomer Density

The calculations of the dimensionless layer monomer density profiles for a dilute solution of phantom ideal ring polymer chains and star polymers with f=4 arms in a Θ-solvent confined in a slit geometry of two parallel walls with repulsive surfaces and for the mixed case of one repulsive and the other inert surface were performed. Furthermore, taking into account the Derjaguin approximation, the dimensionless layer monomer density profiles for phantom ideal ring polymer chains and star polymers immersed in a solution of big colloidal particles with different adsorbing or repelling properties with respect to polymers were calculated. The density-force relation for the above-mentioned cases was analyzed, and the universal amplitude ratio B was obtained. Taking into account the small sphere expansion allowed obtaining the monomer density profiles for a dilute solution of phantom ideal ring polymers immersed in a solution of small spherical particles, or nano-particles of finite size, which are much smaller than the polymer size and the other characteristic mesoscopic length of the system. We performed molecular dynamics simulations of a dilute solution of linear, ring, and star-shaped polymers with N=300, 300 (360), and 1201 (4 × 300 + 1-star polymer with four arms) beads accordingly. The obtained analytical and numerical results for phantom ring and star polymers are compared with the results for linear polymer chains in confined geometries.

Entropic Sampling of Free and Ring Polymer Chains

2005 ◽  
Vol 14 (8) ◽  
pp. 491-504 ◽  
Author(s):  
Nikolai A. Volkov ◽  
Anton A. Yurchenko ◽  
Alexander P. Lyubartsev ◽  
Pavel N. Vorontsov-Velyaminov
Keyword(s):  
Polymer Chains ◽  
Ring Polymer ◽  
Entropic Sampling

Elastic behavior of uniform star polymer chains

2005 ◽  
Vol 41 (7) ◽  
pp. 1596-1604 ◽  
Author(s):  
Yu Shen ◽  
Linxi Zhang
Keyword(s):  
Polymer Chains ◽  
Star Polymer ◽  
Elastic Behavior

scholarly journals Compression and Stretching of Confined Linear and Ring Polymers by Applying Force

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4193
Author(s):  
Wenduo Chen ◽  
Xiangxin Kong ◽  
Qianqian Wei ◽  
Huaiyu Chen ◽  
Jiayin Liu ◽  
...  
Keyword(s):  
Polymer Chains ◽  
Compression Process ◽  
Confined Polymers ◽  
Buckling Instability ◽  
Critical Buckling Force ◽  
Ring Polymers ◽  
Ring Polymer ◽  
Folded Structures ◽  
Two Sides ◽  
Strong Confinement

We use Langevin dynamics to study the deformations of linear and ring polymers in different confinements by applying compression and stretching forces on their two sides. Our results show that the compression deformations are the results of an interplay among of polymer rigidity, degree of confinement, and force applied. When the applied force is beyond the threshold required for the buckling transition, the semiflexible chain under the strong confinement firstly buckles; then comes helical deformation. However, under the same force loading, the semiflexible chain under the weaker confinement exhibits buckling instability and shrinks from the folded ends/sides until it becomes three-folded structures. This happens because the strong confinement not only strongly reduces the buckling wavelength, but also increases the critical buckling force threshold. For the weakly confined polymers, in compression process, the flexible linear polymer collapses into condensed states under a small external force, whereas the ring polymer only shows slight shrinkage, due to the excluded volume interactions of two strands in the crowded states. These results are essential for understanding the deformations of the ring biomacromolecules and polymer chains in mechanical compression or driven transport.

scholarly journals Viscous and Elastic Behavior Attributed to Polymer Entanglements

1968 ◽  
Vol 41 (1) ◽  
pp. 1-22 ◽  
Author(s):  
Roger S. Porter ◽  
William J. MacKnight ◽  
Julian F. Johnson
Keyword(s):  
Molecular Weight ◽  
Relaxation Times ◽  
Polymer Chains ◽  
Polymer Composition ◽  
Elastic Behavior ◽  
Molecular Weights ◽  
Strong Motivation ◽  
Common Observation ◽  
Chain Slippage ◽  
Concentrated Systems

Abstract Polymer chains are separated and behave as individual hydrodynamic units in sufficiently dilute solutions. A minimum polymer molecular weight, dependent on concentration, is necessary to produce the characteristic rheological effects generally attributed to entanglements. The minimum polymer molecular weights and concentrations for which entanglement effects are observed are called the characteristic entanglement compositions. Undiluted polymers exhibit such effects only above some minimum molecular weight. The common observation of entanglement effects indicates that they are not due solely to chemical or structural inhomogeneities. Polymer composition, e.g., polarity and perhaps tacticity, can lead, however, to changes in frequency and strength of entanglements. Entanglements appear to govern many important polymer characteristics, thus providing a strong motivation for their study. Characteristic chain spacings between entanglements have been reported from various viscoelastic experiments, low shear viscometry, nonNewtonian flow, and from relaxation times measured by nuclear magnetic resonance. The different techniques generally give concordant values, although with a wide variation in precision. For a few polymers, e.g., polydimethylsiloxane, the characteristic entanglement spacing has been calculated by each of the four techniques. For others, e.g., polyisobutylene and polystyrene, entanglement spacings have been reported by all except NMR. Entanglement effects have been treated theoretically by analogy with theories of rubber elasticity. Other theories have been developed based on breakage and reformation of entanglements and on polymer chain slippage. Certain of these theories have been shown to have the same formalism and yield similar conclusions. In general, the entanglement hypothesis provides a consistent interpretation for a variety of rheological data on concentrated systems of amorphous polymers, this despite the fact that an entanglement has not as yet been directly “seen”. A discussion of entanglements and the first method of calculating entanglement spacings was given by Mark and Tobolsky. A review in the field of polymer viscosities for concentrated systems has been recently prepared. Experimental details and theoretical derivations are given in texts. The notations used are defined in the Appendix.

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