Statistical Thermodynamics of Polymer Solutions. VII. The Triple‐Contact Contribution to Pairwise Interactions of Linear Chains Differing in Molecular Weight

1969 ◽  
Vol 50 (5) ◽  
pp. 2206-2213 ◽  
Author(s):  
Yukiko Tagami ◽  
Edward F. Casassa
Keyword(s):  
Molecular Weight ◽  
Polymer Solutions ◽  
Statistical Thermodynamics ◽  
Pairwise Interactions ◽  
Linear Chains

scholarly journals Driven Transport of Dilute Polymer Solutions through Porous Media Comprising Interconnected Cavities

2021 ◽  
Vol 5 (2) ◽  
pp. 22
Author(s):  
Karthik Nagarajan ◽  
Shing Bor Chen
Keyword(s):  
Molecular Weight ◽  
Porous Media ◽  
External Force ◽  
Polymer Solutions ◽  
Dissipative Particle Dynamics ◽  
Mean Velocity ◽  
Slip Boundary ◽  
Dilute Polymer Solutions ◽  
Linear Chains ◽  
Pressure Driven Flow

Driven transport of dilute polymer solutions through porous media has been simulated using a recently proposed novel dissipative particle dynamics method satisfying the no-penetration and no-slip boundary conditions. The porous media is an array of overlapping spherical cavities arranged in a simple cubic lattice. Simulations were performed for linear, ring, and star polymers with 12 arms for two cases with the external force acting on (I) both polymer and solvent beads to model a pressure-driven flow; (II) polymer beads only, similar to electrophoresis. When the external force is in the direction of a principal axis, the extent of change in the polymers’ conformation and their alignment with the driving force is more significant for case I. These effects are most pronounced for linear chains, followed by rings and stars at the same molecular weight. Moreover, the polymer mean velocity is affected by its molecular weight and architecture as well as the direction and strength of the imposed force.

Molecular weight scaling in critical polymer solutions

1999 ◽  
Vol 48 (4) ◽  
pp. 372-377 ◽  
Author(s):  
Y. B Melnichenko ◽  
G. D Wignall ◽  
W. A. Van Hook
Keyword(s):  
Molecular Weight ◽  
Polymer Solutions ◽  
Weight Scaling

scholarly journals Viscoelastic Properties of Unentangled Multicyclic Polystyrenes

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 973 ◽  
Author(s):  
Zhi-Chao Yan ◽  
Md. Hossain ◽  
Michael Monteiro ◽  
Dimitris Vlassopoulos
Keyword(s):  
Molecular Weight ◽  
Shear Viscosity ◽  
Viscoelastic Properties ◽  
Dilution Effect ◽  
The Other ◽  
Low Molecular Weight ◽  
Zero Shear Viscosity ◽  
Rouse Model ◽  
Loop Size ◽  
Linear Chains

We report on the viscoelastic properties of linear, monocyclic, and multicyclic polystyrenes with the same low molecular weight. All polymers investigated were found to exhibit unentangled dynamics. For monocyclic polymers without inner loops, a cyclic-Rouse model complemented by the contribution of unlinked chains (whose fraction was determined experimentally) captured the observed rheological response. On the other hand, multicyclic polymers with inner loops were shown to follow a hierarchical cyclic-Rouse relaxation with the outer loops relaxing first, followed by the inner loop relaxation. The influence of unlinked linear chains was less significant in multicyclic polymers with inner loops. The isofrictional zero-shear viscosity decreased with increasing number of constrained segments on the coupling sites, which was attributed to the decreasing loop size and the dilution effect due to the hierarchical relaxation.

scholarly journals Evaporation-induced Rayleigh–Taylor instabilities in polymer solutions

2020 ◽  
Vol 378 (2174) ◽  
pp. 20190533 ◽  
Author(s):  
E. J. Mossige ◽  
V. Chandran Suja ◽  
M. Islamov ◽  
S. F. Wheeler ◽  
Gerald. G. Fuller
Keyword(s):  
Molecular Weight ◽  
Time Scales ◽  
Polymer Solutions ◽  
Critical Concentration ◽  
Polymer Concentration ◽  
Onset Time ◽  
Dense Layer ◽  
Strong Concentration ◽  
Aqueous Polymer ◽  
Gravitational Instabilities

Understanding the mechanics of detrimental convective instabilities in drying polymer solutions is crucial in many applications such as the production of film coatings. It is well known that solvent evaporation in polymer solutions can lead to Rayleigh-Bénard or Marangoni-type instabilities. Here, we reveal another mechanism, namely that evaporation can cause the interface to display Rayleigh–Taylor instabilities due to the build-up of a dense layer at the air–liquid interface. We study experimentally the onset time ( t p ) of the instability as a function of the macroscopic properties of aqueous polymer solutions, which we tune by varying the polymer concentration ( c 0 ), molecular weight and polymer type. In dilute solutions, t p shows two limiting behaviours depending on the polymer diffusivity. For high diffusivity polymers (low molecular weight), the pluming time scales as c 0 − 2 / 3 . This result agrees with previous studies on gravitational instabilities in miscible systems where diffusion stabilizes the system. On the other hand, in low diffusivity polymers the pluming time scales as c 0 − 1 . The stabilizing effect of an effective interfacial tension, similar to those in immiscible systems, explains this strong concentration dependence. Above a critical concentration, c ^ , viscosity delays the growth of the instability, allowing time for diffusion to act as the dominant stabilizing mechanism. This results in t p scaling as ( ν / c 0 ) 2/3 . This article is part of the theme issue ‘Stokes at 200 (Part 1)’.

Effects of molecular weight and concentration on flow properties of concentrated polymer solutions

2007 ◽  
Vol 15 (1) ◽  
pp. 381-406 ◽  
Author(s):  
Shigeharu Onogi ◽  
Shigezo Kimura ◽  
Takashi Kato ◽  
Toshiro Masuda ◽  
Nobuyuki Miyanaga
Keyword(s):  
Molecular Weight ◽  
Polymer Solutions ◽  
Flow Properties
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