Diffusion Coefficient of a Brownian Particle in Equilibrium and Nonequilibrium: Einstein Model and Beyond

Spiechowicz, Jakub; Marchenko, I. G.; Hänggi, Peter; Łuczka, J.

doi:10.3390/e25010042

Cited by 29 publications

(14 citation statements)

References 145 publications

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“…An effective diffusion coefficient ( D eff ) can be extracted using the penetration depth versus time of the particles by fitting with normalΔ x = 2 D normale normalf normalf · t . The values of the fitted parameters are given in Table , and fitting details are given in Supporting Information S5.…”

Section: Resultsmentioning

confidence: 99%

Diffusiophoretic Behavior of Polyelectrolyte-Coated Particles

Akdeniz,

Wood,

Lammertink

2024

Langmuir

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Diffusiophoresis, the movement of particles under a solute concentration gradient, has practical implications in a number of applications, such as particle sorting, focusing, and sensing. For diffusiophoresis in an electrolyte solution, the particle velocity is described by the electrolyte relative concentration gradient and the diffusiophoretic mobility of the particle. The electrolyte concentration, which typically varies throughout the system in space and time, can also influence the zeta potential of particles in space and time. This variation affects the diffusiophoretic behavior, especially when the zeta potential is highly dependent on the electrolyte concentration. In this work, we show that adsorbing a single bilayer (or 4 bilayers) of a polyelectrolyte pair (PDADMAC/PSS) on the surface of microparticles resulted in effectively constant zeta potential values with respect to salt concentration throughout the experimental range of salt concentrations. This allowed a constant potential model for diffusiophoretic transport to describe the experimental observations, which was not the case for uncoated particles in the same electrolyte system. This work highlights the use of simple polyelectrolyte pairs to tune the zeta potential and maintain constant values for precise control of diffusiophoretic transport.

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Section: Resultsmentioning

confidence: 99%

Diffusiophoretic Behavior of Polyelectrolyte-Coated Particles

Akdeniz,

Wood,

Lammertink

2024

Langmuir

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“…However, it is not straightforward to a priori identify the physical origin of such a nonlinear connection between quantities that refer to essentially dynamic and equilibrium processes, i.e., diffusion ( D X,p ) and chemical partitioning equilibria of components at an interface ( K w,p ), respectively. As a hint to the underlying connections, we mention that complex nonlinear expressions combining dynamic and equilibrium quantities can be found in the literature on advanced physical modeling. , For example, Lifson and Jackson established an expression for the diffusion coefficient of an inertial particle in a fixed static energy field; we recall that the Gibbs free energy of contaminant adsorption on a surface can be estimated in our case from the relevant thermodynamic constant, K w,p .…”

Section: Resultsmentioning

confidence: 99%

Effect of Polymer Aging on Uptake/Release Kinetics of Metal Ions and Organic Molecules by Micro- and Nanoplastics: Implications for the Bioavailability of the Associated Compounds

Town,

van Leeuwen,

Duval

2023

Environ. Sci. Technol.

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The main driver of the potential toxicity of micro- and nanoplastics toward biota is often the release of compounds initially present in the plastic, i.e., polymer additives, as well as environmentally acquired metals and/or organic contaminants. Plastic particles degrade in the environment via various mechanisms and at different rates depending on the particle size/geometry, polymer type, and the prevailing physical and chemical conditions. The rate and extent of polymer degradation have obvious consequences for the uptake/release kinetics and, thus, the bioavailability of compounds associated with plastic particles. Herein, we develop a theoretical framework to describe the uptake and release kinetics of metal ions and organic compounds by plastic particles and apply it to the analysis of experimental data for pristine and aged micro- and nanoplastics. In particular, we elucidate the contribution of transient processes to the overall kinetics of plastic reactivity toward aquatic contaminants and demonstrate the paramount importance of intraparticulate contaminant diffusion.

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“…Mechanism of this type are well-known in diffusion theory. Spiechowicz et al 25 describe a "nonequilibrium situation in which the diffusion of a periodically driven Brownian particle moving in a periodic potential decreases with increasing temperature within a finite temperature window" and "identify (it) as the cause for this nonintuitive behavior a dominant deterministic mechanism consisting of a few unstable periodic orbits embedded into a chaotic attractor together with thermal noise-induced dynamical changes upon varying temperature".…”

Section: Discussionmentioning

confidence: 99%

NMR Studies of the Rehydroxylation of Ceramic Materials with Respect to Rehydroxylation Dating

Avramovska,

Freude,

Schwieger

et al. 2023

J. Phys. Chem. C

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Monitoring the rehydroxylation (RHX) in ceramic samples after firing was introduced in archeology as the RHX dating in order to determine the time elapsed since the firing of a ceramic artifact. But the mechanisms of hydroxyl transport during the RHX mechanism are still largely unclear. The present study investigates hydroxyl groups of three at 800 °C fired ceramics upon hydrothermal treatment of the samples. The rehydroxylation of the ceramics between 600 and 200 °C results in an increase of less than a factor of 1.5 for most samples, whereas early studies showed that the decrease of the hydroxyl concentration is a factor of about 10 for the basic powder material in the dehydroxylation range 200–800 °C. A sieve fraction of 100–140 μm of ceramic materials crushed in a mortar was used for the magic-angle spinning (MAS) NMR experiments because larger particles and of course the fired cylinders (10 mm diameter) of the ceramic materials do not rotate at higher frequencies. The less accurate static NMR experiments (without MAS) on the ceramic pieces with 1 cm diameter did not show significant differences because the ceramic is porous. H/D tracer exchange experiments show that H/D exchange time constants do not significantly depend on temperature. Therefore, the hydroxyl transport mechanism cannot be described by an activation energy like for normal diffusion. We explain the transport of hydroxylation by a quantum Brownian diffusion of hydrogen atoms between hydroxyl groups and (opening of) constrained bonds in the near neighborhood.

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Diffusion Coefficient of a Brownian Particle in Equilibrium and Nonequilibrium: Einstein Model and Beyond

Cited by 29 publications

References 145 publications

Diffusiophoretic Behavior of Polyelectrolyte-Coated Particles

Diffusiophoretic Behavior of Polyelectrolyte-Coated Particles

Effect of Polymer Aging on Uptake/Release Kinetics of Metal Ions and Organic Molecules by Micro- and Nanoplastics: Implications for the Bioavailability of the Associated Compounds

NMR Studies of the Rehydroxylation of Ceramic Materials with Respect to Rehydroxylation Dating

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