scholarly journals Polymer brush bilayers under stationary shear motion at linear response regime: A theoretical approach

2019 ◽  
Author(s):  
Mike Edwards
Keyword(s):  
Statistical Mechanics ◽  
Theoretical Approach ◽  
Linear Response ◽  
Soft Matter ◽  
Polymer Brush ◽  
Shear Rates ◽  
Linear Response Regime ◽  
Shear Motion ◽  
Small Shear ◽  
Standing Problem

ABSTRACTStatistical mechanics is employed to tackle the problem of polymer brush bilayers under stationary shear motion. The article addresses, solely, the linear response regime in which the polymer brush bilayers behave very much similar to the Newtonian fluids. My approach to this long-standing problem split drastically from the work already published Kreer, T, Soft Matter, 12, 3479 (2016). It has been thought for many decades that the interpenetration between the brushes is source of the friction between the brush covered surfaces sliding over each other. Whiles, the present article strongly rejects the idea of interpenetration length in that issue. Instead, here, I show that structure of the whole system is significant in friction between brush covered surfaces and the interpenetration is absolutely insignificant. The results of this research would blow one’s mind about how the polymer brush bilayers respond at small shear rates.

scholarly journals Polymer Brush Bilayers under Stationary Shear Motion at Non-Linear Response Regime: An Impressive Theoretical Approach

2019 ◽  
Author(s):  
Mike Edwards
Keyword(s):  
Linear Response ◽  
Polymer Brush ◽  
Main Idea ◽  
Shear Direction ◽  
Shear Rates ◽  
Global Restructuring ◽  
Linear Response Regime ◽  
Non Linear ◽  
Shear Motion ◽  
Physical Quantities

The present article addresses the long-standing problem of the polymer brush bilayers under stationary shear ow at non-linear response regime where the system gets a non-Newtonian uid. The main idea behind this research would be the fact that the immense lubricity of the polymer brush bilayers originates from a global restructuring that takes place at large shear rates. It is shown here that physical quantities like, stress tensor, viscosity tensor, the friction coefficient and the chain extensions could become dependent on the shear rate at non-Newtonian regime. Apparently, the sub-linear scaling of the physical quantities at large shear rates is solely due to the fact that the hains stretch in the shear direction.

scholarly journals Interpenetration between a polymer brush and a polymer star at thermal equilibrium: A theoretical approach

2018 ◽  
Author(s):  
Mike Edwards
Keyword(s):  
Density Functional Theory ◽  
Theoretical Approach ◽  
Thermal Equilibrium ◽  
Density Functional ◽  
Polymer Brush ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Theory Framework ◽  
Absorption Transitions ◽  
Standing Problem

By means of the density functional theory framework I tackle the long-standing problem of a polymer star interpenetrating with a polymer brush at thermal equilibrium. Remarkably, the star is repelled to the outside of the brush once it sucks into the brush. It turns out that there could be a highly fluctuating region at the brush edge. The highly fluctuating region would be responsible for discontinuous absorption transitions by brushes. However, up to an small interpenetration length, below which asphericity of the star is maintained, the star gets collapsed by sucking more and more into the brush.

scholarly journals Transport in one-dimensional integrable quantum systems

2020 ◽  
Author(s):  
Jesko Sirker
Keyword(s):  
Transport Properties ◽  
Spin Chain ◽  
Linear Response ◽  
Summer School ◽  
Condensed Matter ◽  
Quantum Systems ◽  
Integrable Models ◽  
One Dimensional ◽  
Integrable Quantum ◽  
Linear Response Regime

These notes are based on a series of three lectures given at the Les Houches summer school on ’Integrability in Atomic and Condensed Matter Physics’ in August 2018. They provide an introduction into the unusual transport properties of integrable models in the linear response regime focussing, in particular, on the spin-1/21/2 XXZ spin chain.

Linear Response Theory

2006 ◽  
Author(s):  
Abraham Nitzan
Keyword(s):  
Statistical Mechanics ◽  
Linear Response ◽  
Ad Hoc ◽  
Linear Response Theory ◽  
Perturbative Expansion ◽  
General Nature ◽  
Response Theory ◽  
Equilibrium Statistical Mechanics ◽  
Standard Application ◽  
Statistical Mechanical

Equilibrium statistical mechanics is a first principle theory whose fundamental statements are general and independent of the details associated with individual systems. No such general theory exists for nonequilibrium systems and for this reason we often have to resort to ad hoc descriptions, often of phenomenological nature, as demonstrated by several examples in Chapters 7 and 8. Equilibrium statistical mechanics can however be extended to describe small deviations from equilibrium in a way that preserves its general nature. The result is Linear Response Theory, a statistical mechanical perturbative expansion about equilibrium. In a standard application we start with a system in thermal equilibrium and attempt to quantify its response to an applied (static- or time-dependent) perturbation. The latter is assumed small, allowing us to keep only linear terms in a perturbative expansion. This leads to a linear relationship between this perturbation and the resulting response. Let us make these statements more quantitative. Consider a system characterized by the Hamiltonian Ĥ0.

Deformation of metallic liquid drop by electric field for contacts in molecular–organic electronics

2009 ◽  
Vol 465 (2106) ◽  
pp. 1799-1808 ◽  
Author(s):  
M. Bag ◽  
D. Gupta ◽  
N. Arun ◽  
K.S. Narayan
Keyword(s):  
Solid State ◽  
Surface Energy ◽  
Electric Field ◽  
Linear Response ◽  
Liquid Drop ◽  
Electrostatic Energy ◽  
Critical Voltage ◽  
Metallic Liquid ◽  
Linear Response Regime ◽  
Polymer Electronics

We study and use the behaviour of a metallic liquid drop in the presence of an external electric field (EF). The droplet profile is governed by the stabilizing surface energy and the destabilizing electrostatic energy, with a critical voltage beyond which the droplet becomes unstable. We explore the EF-induced behaviour of low melting temperature alloy in the liquid state and observe that the droplet modifications in the linear response regime can be retained upon cooling the drop to the solid state. We demonstrate that this procedure can be used as an electrode with precise dimensions for applications in molecular and polymer electronics.

Sign in / Sign up

Export Citation Format

Share Document