scholarly journals Statistical Behaviours of Semiflexible Polymer Chains Stretched in Rectangular Tubes

2018 ◽  
Author(s):  
Jizeng Wang ◽  
Kai Li
Keyword(s):  
Brownian Dynamics ◽  
Numerical Solutions ◽  
Persistence Length ◽  
Polymer Chains ◽  
Chain Model ◽  
Semiflexible Polymer ◽  
Dynamics Simulations ◽  
Wormlike Chain Model ◽  
Deflection Theory ◽  
Brownian Dynamics Simulations

We quantitatively investigated the statistical behaviors of semiflexible polymer chains, which are simultaneously subjected to force stretching and rectangular tube confinement. Based on the wormlike chain model and Odijk deflection theory, we derived a new deflection length, by which new compact formulas are obtained for the confinement free energy and force-confinement-extension relation. These newly derived formulas have been justified by numerical solutions of an eigenvalue problem associated with the Fokker-Planck governing equation and extensive Brownian dynamics simulations based on the so-called Generalized Bead-Rod (GBR) model. We found that, comparing to the classical deflection theory, these new formulas are valid for a much extended range of the confinement-size /persistence-length ratio, and have no adjustable fitting parameters for sufficient long semiflexible chains in the whole deflection regime.

scholarly journals Statistical Behaviors of Semiflexible Polymer Chains Stretched in Rectangular Tubes

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 260 ◽  
Author(s):  
Jizeng Wang ◽  
Kai Li
Keyword(s):  
Brownian Dynamics ◽  
Numerical Solutions ◽  
Persistence Length ◽  
Polymer Chains ◽  
Chain Model ◽  
Semiflexible Polymer ◽  
Dynamics Simulations ◽  
Wormlike Chain Model ◽  
Deflection Theory ◽  
Brownian Dynamics Simulations

We investigated the statistical behaviors of semiflexible polymer chains, which were simultaneously subjected to force stretching and rectangular tube confinement. Based on the wormlike chain model and Odijk deflection theory, we derived a new deflection length, by using which new compact formulas were obtained for the confinement free energy and force–confinement–extension relations. These newly derived formulas were justified by numerical solutions of the eigenvalue problem associated with the Fokker–Planck governing equation and extensive Brownian dynamics simulations based on the so-called generalized bead-rod (GBR) model. We found that, compared to classical deflection theory, these new formulas were valid for a much more extended range of the confinement size/persistence length ratio and had no adjustable fitting parameters for sufficiently long semiflexible chains in the whole deflection regime.

scholarly journals Stretching Wormlike Chains in Narrow Tubes of Arbitrary Cross-Sections

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2050
Author(s):  
Ming Li ◽  
Jizeng Wang
Keyword(s):  
Cross Sections ◽  
Brownian Dynamics ◽  
Statistical Physics ◽  
Polymer Chains ◽  
Chain Model ◽  
Mode Decomposition ◽  
Dynamics Simulations ◽  
Single Formula ◽  
Wormlike Chain Model ◽  
Confined Polymer Chains

We considered the stretching of semiflexible polymer chains confined in narrow tubes with arbitrary cross-sections. Based on the wormlike chain model and technique of normal mode decomposition in statistical physics, we derived a compact analytical expression on the force-confinement-extension relation of the chains. This single formula was generalized to be valid for tube confinements with arbitrary cross-sections. In addition, we extended the generalized bead-rod model for Brownian dynamics simulations of confined polymer chains subjected to force stretching, so that the confinement effects to the chains applied by the tubes with arbitrary cross-sections can be quantitatively taken into account through numerical simulations. Extensive simulation examples on the wormlike chains confined in tubes of various shapes quantitatively justified the theoretically derived generalized formula on the force-confinement-extension relation of the chains.

BROWNIAN DYNAMICS SIMULATIONS OF A DOUBLE-END ANCHORED POLYMER UNDER A PERIODIC OSCILLATORY FORCE

2011 ◽  
Vol 25 (14) ◽  
pp. 1899-1904 ◽  
Author(s):  
QIYI ZHANG ◽  
KEREN LI ◽  
HAIYAN TANG
Keyword(s):  
Brownian Dynamics ◽  
Hysteresis Cycle ◽  
Middle Segment ◽  
Semiflexible Polymer ◽  
Single Curve ◽  
Polymer Anchored ◽  
Dynamics Simulations ◽  
Brownian Dynamics Simulations ◽  
Oscillatory Force

We present results of the dynamics of a single polymer, anchored at both ends and subjected to a periodic oscillatory force at a middle segment. Via Brownian dynamics simulations, the influences of the periodicity of the forcing on the shape of the orbit in the position-force plane have been investigated for flexible and semiflexible polymer. The shape of the orbit exhibits in the form of hysteresis cycle or a single curve.

scholarly journals Structure evolution of suspensions under time-dependent electric or magnetic field

2021 ◽  
Author(s):  
Konstantinos Manikas ◽  
Markus Hütter ◽  
Patrick D. Anderson
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Brownian Dynamics ◽  
Thermal Fluctuations ◽  
Time Dependent ◽  
Structure Evolution ◽  
Strength Increase ◽  
Large Rotation ◽  
Dynamics Simulations ◽  
Brownian Dynamics Simulations

AbstractThe effect of time-dependent external fields on the structures formed by particles with induced dipoles dispersed in a viscous fluid is investigated by means of Brownian Dynamics simulations. The physical effects accounted for are thermal fluctuations, dipole-dipole and excluded volume interactions. The emerging structures are characterised in terms of particle clusters (orientation, size, anisotropy and percolation) and network structure. The strength of the external field is increased in one direction and then kept constant for a certain amount of time, with the structure formation being influenced by the slope of the field-strength increase. This effect can be partially rationalized by inhomogeneous time re-scaling with respect to the field strength, however, the presence of thermal fluctuations makes the scaling at low field strength inappropriate. After the re-scaling, one can observe that the lower the slope of the field increase, the more network-like and the thicker the structure is. In the second part of the study the field is also rotated instantaneously by a certain angle, and the effect of this transition on the structure is studied. For small rotation angles ($$\theta \le 20^{{\circ }}$$ θ ≤ 20 ∘ ) the clusters rotate but stay largely intact, while for large rotation angles ($$\theta \ge 80^{{\circ }}$$ θ ≥ 80 ∘ ) the structure disintegrates and then reforms, due to the nature of the interactions (parallel dipoles with perpendicular inter-particle vector repel each other). For intermediate angles ($$20<\theta <80^{{\circ }}$$ 20 < θ < 80 ∘ ), it seems that, during rotation, the structure is altered towards a more network-like state, as a result of cluster fusion (larger clusters). The details provided in this paper concern an electric field, however, all results can be projected into the case of a magnetic field and paramagnetic particles.

scholarly journals Influence of size polydispersity on magnetic field tunable structures in magnetic nanofluids containing superparamagnetic nanoparticles.

2021 ◽  
Author(s):  
Dillip Kumar Mohapatra ◽  
Philip James Camp ◽  
John Philip
Keyword(s):  
Magnetic Field ◽  
Particle Size ◽  
Light Scattering ◽  
Optical Microscopy ◽  
Brownian Dynamics ◽  
Phase Contrast ◽  
Superparamagnetic Nanoparticles ◽  
Magnetic Nanofluids ◽  
Dynamics Simulations ◽  
Brownian Dynamics Simulations

We probe the influence of particle size polydispersity on field-induced structures and structural transitions in magnetic fluids (ferrofluids) using phase contrast optical microscopy, light scattering and Brownian dynamics simulations. Three...

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