Wet and dry internal friction can be measured with the Jarzynski equality

Kailasham, R.; Chakrabarti, Ramananda; Prakash, J. Ravi

doi:10.1103/physrevresearch.2.013331

Cited by 18 publications

(9 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…one from the difference in energies of the configurations associated with the positioning of different residues near or far from each other [72] which is accounted for by internal friction in polymer chains [73] and another from the net effect of the active forcing experienced by the particle. In this case the MFPT can be useful to describe the looping time of a polymer in an active bath [74].…”

Section: Influence Of Additional Ruggedness In Active Landscapementioning

confidence: 99%

Escape of a passive particle from activity-induced energy landscape: Emergence of slow and fast effective diffusion

Chaki,

Chakrabarti

2020

Preprint

Self Cite

View full text Add to dashboard Cite

Spontaneous persistent motions driven by active processes play a central role to maintain the living cells far from equilibrium. In the majority of the research works, the steady state dynamics of an active system has been described in terms of an effective temperature. By contrast, we have examined a prototype model for diffusion in an activity-induced rugged energy landscape to describe the slow dynamics of a tagged particle in a dense active environment. The expression for the mean escape time from the active rugged energy landscape holds only in the limit of low activity and the mean escape time from the rugged energy landscape increases with activity. The precise form of the active correlation will determine whether the mean escape time will depend on the persistence time or not. The active rugged energy landscape approach also allows an estimate of non-equilibrium effective diffusivity characterizing the slow diffusive motion of the tagged particle due to activity. On the other hand, in a dilute environment, high activity augments the diffusion of the tagged particle. The enhanced diffusion can be attributed to an effective temperature, higher than the ambient temperature and is used to calculate the Kramers' mean escape time, which decreases with activity. Our results have direct relevance to recent experiments on tagged particle diffusion in condensed phases. I. INTRODUCTIONSystems composed of active particles represent a class of driven non-equilibrium systems in which the driving forces are direct, isotropic and controlled locally rather than globally [1,2]. They can either be found in biological systems such as bacterial colonies [3], motile cells in tissues [4], cytoskeleton in living cells [5] or are realized artificially such as catalytic Janus particles [6]. While the former are typically self-propelled by the chemical energy

show abstract

Section: Influence Of Additional Ruggedness In Active Landscapementioning

confidence: 99%

Escape of a passive particle from activity-induced energy landscape: Emergence of slow and fast effective diffusion

Chaki,

Chakrabarti

2020

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Hydrodynamic interactions have been successfully incorporated over the past several decades in computational studies of polymer solution dynamics in the dilute concentration regime, both by methods that treat the solvent explicitly, such as nonequilibrium molecular dynamics (NEMD) [31][32][33][34][35], and by Brownian dynamics (BD) simulations [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51]. In BD, solvent degrees of freedom are eliminated completely and their effect is taken into account through long-range dynamic correlations in the stochastic displacements of the beads.…”

Section: Brownian Dynamics Of Associative Polymer Solutionsmentioning

confidence: 99%

Universal scaling and characterisation of gelation in associative polymer solutions

Santra,

Dünweg,

Prakash

2020

Preprint

Self Cite

View full text Add to dashboard Cite

A multi-particle Brownian dynamics simulation algorithm with a Soddemann-Duenweg-Kremer potential that accounts for pairwise excluded volume interactions between both backbone monomers and associating groups (stickers) on a chain, is used to describe the static behaviour of associative polymer solutions, across a range of concentrations into the semidilute unentangled regime. Predictions for the fractions of stickers bound by intra-chain and inter-chain association, as a function of system parameters such as the number of stickers on a chain, the number of backbone monomers between stickers, the solvent quality, and monomer concentration are obtained. A systematic comparison between simulation results and scaling relations predicted by the mean-field theory of Dobrynin (Macromolecules, 37, 3881, 2004) is carried out. Different regimes of scaling behaviour are identified by the theory depending on the monomer concentration, the density of stickers on a chain, and whether the solvent quality for the backbone monomers corresponds to θ or good solvent conditions. Simulation results validate the predictions of the mean-field theory across a wide range of parameter values in all the scaling regimes, except for one regime corresponding to backbone monomers under good solvent conditions at relatively high concentrations. The value of the des Cloizeaux exponent, θ2 = 1/3, proposed by Dobrynin for sticky polymer solutions, is shown to lead to a collapse of simulation data for all the scaling relations considered here. Three different signatures for the characterisation of gelation are identified, with each leading to a different value of the concentration at the sol-gel transition. The Flory-Stockmayer expression relating the degree of inter-chain conversion at the sol-gel transition to the number of stickers on a chain is found not to be validated by simulations, while an alternative expression is satisfied by all three gelation signatures. Simulation results confirm the prediction of scaling theory for the gelation line that separates sol and gel phases, when the revised Flory-Stockmayer expression is used. Phase separation is found to occur with increasing concentration for systems in which the backbone monomers are under θ-solvent conditions, and is shown to coincide with a breakdown in the predictions of scaling theory.

show abstract

“…More recently, however, the JE has been used to compute not only free-energy differences but also dissipative work. For example, internal friction was studied using a simple spring-dashpot model of a polymer [19] and the JE. In the next section we detail some aspects of the JE for calculation of free-energy curves ∆A(z) for interaction surfaces including dissipative work.…”

Section: Introductionmentioning

confidence: 99%

Dissipation and adhesion hysteresis between (010) forsterite surfaces using molecular-dynamics simulation and the Jarzynski equality

Doan,

Schelling

2021

Preprint

View full text Add to dashboard Cite

Dissipation and adhesion is important in many areas of materials science, including friction and lubrication, cold spray deposition, and micro-electromechanical systems (MEMS). Another interesting problem is the adhesion of mineral grains during the early stages of planetesimal formation in the early solar system. Molecular-dynamics (MD) simulation has often been used to elucidate dissipative properties, most often in the simulation of sliding friction. In this paper, we demonstrate how the reversible and irreversible work associated with interactions of planar surfaces can be calculated using the dynamical contact simulation approach based on MD and empirical potentials. Moreover, it is demonstrated how the approach can obtain the free-energy ∆A(z) as a function of separation between two slabs using the Jarzynksi equality applied to an ensemble of simulations which deviate significantly from equilibrium. Furthermore, the dissipative work can also be obtained using this approach, without the need to compute an entire cycle from approach to retraction. It is expected that this approach might be used to efficiently compute dissipative properties of different system, which might enable the application of more intensive approaches including densityfunctional theory. In this paper, we present results obtained for forsterite surfaces both with and without MgO-vacancy surface defects. It is shown that strong dissipation is possible when MgO-vacancy defects are present. The mechanism for strong dissipation is connected to the tendency of less strongly-bound surface units undergoing large displacements including mass transfer between the two surfaces. Systems with strong dissipation tend to exhibit a long-tailed distribution rather than the Gaussian distribution often anticipated in near-equilibrium applications of the JE.

show abstract

Wet and dry internal friction can be measured with the Jarzynski equality

Cited by 18 publications

References 68 publications

Escape of a passive particle from activity-induced energy landscape: Emergence of slow and fast effective diffusion

Escape of a passive particle from activity-induced energy landscape: Emergence of slow and fast effective diffusion

Universal scaling and characterisation of gelation in associative polymer solutions

Dissipation and adhesion hysteresis between (010) forsterite surfaces using molecular-dynamics simulation and the Jarzynski equality

Contact Info

Product

Resources

About