Bulk and interfacial shear thinning of immiscible polymers
Sandra Barsky,Mark O. Robbins +1 more
TLDR
Nonequilibrium molecular-dynamics simulations are used to study the shear-thinning behavior of immiscible symmetric polymer blends, which correlates more closely with a decrease in the component of the radius of gyration along the velocity gradient than with elongation along the flow.Abstract:
Nonequilibrium molecular-dynamics simulations are used to study the shear-thinning behavior of immiscible symmetric polymer blends. The phase-separated polymers are subjected to a simple shear flow imposed by moving a wall parallel to the fluid-fluid interface. The viscosity begins to shear thin at much lower rates in the bulk than at the interface. The entire shear-rate dependence of the interfacial viscosity is consistent with a shorter effective chain length s(*) that also describes the width of the interface. This s(*) is independent of chain length N and is a function only of the degree of immiscibility of the two polymers. Changes in polymer conformation are studied as a function of position and shear rate. Shear thinning correlates more closely with a decrease in the component of the radius of gyration along the velocity gradient than with elongation along the flow. At the interface, this contraction of chains is independent of N and consistent with the bulk behavior for chains of length s(*). The distribution of conformational changes along chains is also studied. Central regions begin to stretch at a shear rate that decreases with increasing N, while shear induced changes at the ends of chains are independent of N.read more
Citations
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Interfacial water at hydrophobic and hydrophilic surfaces: slip, viscosity, and diffusion.
TL;DR: The dynamics and structure of water at hydrophobic and hydrophilic diamond surfaces is examined via non-equilibrium Molecular Dynamics simulations and the effect of the Lennard-Jones cutoff length on the interfacial properties is discussed.
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Structure and friction of stearic acid and oleic acid films adsorbed on iron oxide surfaces in squalane.
TL;DR: The structure and friction of fatty acid surfactant films adsorbed on iron oxide surfaces lubricated by squalane are examined using large-scale molecular dynamics simulations, and the effects of unsaturation in the tail group are highlighted.
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Shear viscosity of a supercooled polymer melt via nonequilibrium molecular dynamics simulations
Fathollah Varnik,Kurt Binder +1 more
TL;DR: In this paper, the authors compute the shear viscosity of a glass forming polymer melt at temperatures ranging from the normal liquid state down to the supercooled state using nonequilibrium molecular dynamics simulations.
Journal ArticleDOI
Nonlinear Shear Rheology of Entangled Polymer Rings
Daniele Parisi,Daniele Parisi,Salvatore Costanzo,Salvatore Costanzo,Youncheol Jeong,Junyoung Ahn,Taihyun Chang,Dimitris Vlassopoulos,Jonathan D. Halverson,Kurt Kremer,Ting Ge,Michael Rubinstein,Michael Rubinstein,Gary S. Grest,Watee Srinin,Alexander Y. Grosberg +15 more
TL;DR: In this article, the steady-state shear viscosity of unconcatenated ring polymer melts as a function of the shear rate γ is studied by a combination of experiments, simulations, and theory.
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Reaction Kinetics of Multiphase Polymer Systems under Flow
TL;DR: In this paper, it was shown that reaction kinetics of two immiscible reactive polymers can be significantly higher than that of small molecule analogues under sufficient mixing, attributed to the combined effects of increasing collision probability originated from mixing-induced interfacial area generation, longer relaxation time of reactive polymer chains, and eventually interfacial slip.
References
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Book
The theory of polymer dynamics
Masao Doi,Sam F. Edwards +1 more
TL;DR: In this article, the viscoelasticity of polymeric liquids was studied in the context of rigid rod-like polymers and concentrated solutions of rigid rods like polymers.
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