A simulation study on the subdiffusion of polymer chains in crowded environments containing nanoparticles

Abstract

Polymer chains in crowded environments often show subdiffusive behavior. We adopt molecular dynamics simulations to study the conditions for the subdiffusion of polymer chains in crowded environments containing randomly distributed,...

Langevin dynamics simulation on optimal conditions for large and stable loops of adsorbed homopolymers on substrates

“…It was found that polymer chains exhibit subdiffusion at low c p due to the strong adsorption on nanoparticles whereas they exhibit normal diffusion at high c p because the adsorption is weakened by inter-polymer interactions. 21 In this subsection, the adsorption and dynamics of adsorbed polymer chains are studied under different polymer concentrations while keeping ε sp = 2 and N = 64 as constants.…”

“…The simulation results reflect two effects of increasing polymer concentrations: (1) increasing the number of adsorbed polymer chains 22 and (2) weakening the adsorption extent of adsorbed polymer chains. 21,42 Fig. 7 presents the distribution of M at three polymer concentrations.…”

“…[9][10][11] Molecular dynamics (MD) simulation proved that entanglement between the loop and free chains inhibits the motion of free chains. 15 The conformation of the adsorption layer is affected by many factors, such as the chain length, 1,2,5,14,[16][17][18][19] attraction strength of the substrate [17][18][19][20] and polymer concentration, 6,16,[21][22][23][24] as reported in theoretical, experimental and simulation studies. For instance, Scheutjens et al found that, in the extremely dilute solution, the average size of loops first increased and then reached a saturation value with an increase in the chain length.…”

A new framework for computing a general local self-diffusion coefficient using statistical mechanics

“…Similar extensions that are applied for global diffusivity will be required to treat such systems locally. [31][32][33][34] In the systems studied here, this is not an issue. However, for other systems examination of the convergence of the integrals could be used to identify regions of the system where diffusion is anomalous.…”

New Framework for Computing a General Local Self-Diffusion Coefficient Using Statistical Mechanics

“…We note that in cases where anomalous diffusion occurs, the integrals of the correlation functions will decay to zero (subdiffusive) or not converge (superdiffusive) just as occurs for standard Green–Kubo relations in bulk systems. Similar extensions that are applied for global diffusivity will be required to treat such systems locally. − In the systems studied here, this is not an issue. However, for other systems, examination of the convergence of the integrals could be used to identify regions of the system where diffusion is anomalous.…”