Thermo-osmotic transport in nanochannels grafted with pH-responsive polyelectrolyte brushes modelled using augmented strong stretching theory

Sivasankar, Vishal Sankar; Etha, Sai Ankit; Sachar, Harnoor Singh; Das, Siddhartha

doi:10.1017/jfm.2021.281

Cited by 11 publications

(12 citation statements)

References 89 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As a general case for arbitrary initial conditions, the eigenvalue problem may depend on the azimuthal angle, and Bessel functions of higher orders may need to be considered. In addition, our simple analytical procedure can be conveniently applied to reactive transport problems in laminar or turbulent flows (Ng & Yip 2001), natural streams (Valentine & Wood 1977;Sandoval et al 2019;Wu et al 2021), wetland flows (Yang et al 2020;Guan et al 2021), electroosmotic flows (Abdollahzadeh, Saidi & Sadeghi 2017;Mederos et al 2020;Sadeghi et al 2020;Sivasankar et al 2021), oscillatory flows (Ng 2006;Paul & Mazumder 2011;Mazumder & Paul 2012;Debnath et al 2019;Mederos et al 2020), etc. These applications are of practical interest in chemistry, biology and hydraulic engineering.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Analytical solutions for reactive shear dispersion with boundary adsorption and desorption

Jiang

Zeng

et al. 2022

J. Fluid Mech.

View full text Add to dashboard Cite

Surface reactions such as the adsorption and desorption at boundaries are very common for solute dispersion in many applications of chemistry, biology, hydraulics, etc. To study how reversible adsorption affects the transient dispersion, Zhang, Hesse & Wang (J. Fluid Mech., vol. 828, 2017, pp. 733–752) have investigated the temporal evolution of moments using the Laplace transform method. Owing to difficulties introduced by the adsorption–desorption boundary condition, great challenges arise from the inverse Laplace transform: dealing with the singularities by the residue theorem can tremendously increase complexities. This work provides a much simpler analytical method to derive solutions in a more compact form that is valid for the entire range of the reactive transport process. Such a progress demonstrates that the classic framework of separation of variables can be extended and applied to this more general adsorption–desorption condition, based on which higher-order statistics including skewness and kurtosis can be explicitly explored in practice. Also extended is Gill's generalised dispersion model for solute concentration distributions, which can now address the entire transient dispersion characteristics, instead of just applied for the long-time asymptotic reactive process as done previously. Regarding the most classic Taylor dispersion problem, we investigate the influence of the reversible adsorption–desorption on the solute cloud in a tube flow. Not only the transient dispersion characteristics of transverse-average concentration distribution but also those of the bulk, surface and total-average distributions are discussed. We further investigate the influence of initial conditions on the non-uniformity of the transient dispersion over the cross-section.

show abstract

Section: Discussionmentioning

confidence: 99%

“…2020; Sivasankar et al. 2021), oscillatory flows (Ng 2006; Paul & Mazumder 2011; Mazumder & Paul 2012; Debnath et al. 2019; Mederos et al.…”

Section: Discussionmentioning

confidence: 99%

Analytical solutions for reactive shear dispersion with boundary adsorption and desorption

Jiang

Zeng

et al. 2022

J. Fluid Mech.

View full text Add to dashboard Cite

show abstract

“…The study unravels an increase of the brush thickness due to the excluded volume interaction which is originated from polyelectrolyte inter-segmental repulsion, as well as a variation in the brush thickness for γa 3 , attributed to counterion-induced osmotic swelling of the brushes. Furthermore, with the help of the augmented strong stretching theory, the authors provided the fascinating theoretical analysis [40][41][42][43][44] of liquid transport driven by an axial temperature gradient, concentration gradient, electric potential gradient in polyelectrolyte-brush-grafted nanofluidic channel. However, to the best of our knowledge, there is no researcher which discusses how the excluded volume interaction and the expanded form of the mass action law affect the electrostatic interaction and structure between pH-responsive polyelectrolyte brushes.…”

Section: Introductionmentioning

confidence: 99%

Structural and electrostatic properties between pH-responsive polyelectrolyte brushes studied by augmented strong stretching theory

Sin¹

2022

The Journal of Chemical Physics

View full text Add to dashboard Cite

In this paper, we study electrostatic and structural properties between pH-responsive polyelectrolyte brushes by using a strong stretching theory accounting for excluded volume interactions, the density of polyelectrolyte chargeable sites and the Born energy difference between the inside and outside of the brush layer.In a free energy framework, we obtain self-consistent field equations to determine electrostatic properties between two pH-responsive polyelectrolyte brushes. We elucidate that in the region between two pH-responsive polyelectrolyte brushes, electrostatic potential at the centerline and osmotic pressure increase not only with excluded volume interaction, but also with density of chargeable sites on a polyelectrolyte molecule. Importantly, we clarify that when two pH-responsive polyelectrolyte brushes approach each other, the brush thickness becomes short and that a large excluded volume interaction and a large density of chargeable sites yield the enhanced contract of polyelectrolyte brushes. In addition, we also demonstrate how the influence of such quantities as pH, the number of Kuhn monomers, the density of charged sites, the lateral separation between adjacent polyelectrolyte brushes, Kuhn length on the electrostatic and structural properties between the two polyelectrolyte brushes is affected by the exclusion volume interaction. Finally, we investigate the influence of Born energy difference on the thickness of polyelectrolyte brushes and the osmotic pressure between two pH-responsive polyelectrolyte brushes.

show abstract

“…The polyelectrolyte (PE) should be distinguished from the neutral polymer due to its ability to dissociate charges in solvents, resulting in a charged polymer chain (macro-ion) and mobile counter-ions. The PE brush plays an important role in flow fields at narrow spaces, for example, the critical effects of flow-induced deformation of the PE or transport at PE-grafted interfaces in nanochannels where the brush height is comparable to the channel Micromachines 2021, 12, 1475 2 of 13 width [15][16][17][18]. For microfluidic channels whose width is much larger than the brush height, changes of flow field are generally observed near the channel wall rather than in the bulk region.…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies on PE brush-grafted nanochannel employed the Poisson-Boltzmann (PB) equation to estimate the electrostatic potential, assuming that the ion concentration within the brush layer follows the Boltzmann distribution [15][16][17][18]. This PB equation has been widely employed in the literature concerning microfluidics in microchannels [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Electrostatic Potential Analysis in Polyelectrolyte Brush-Grafted Microchannels Filled with Polyelectrolyte Dispersion

Chun

2021

Micromachines

View full text Add to dashboard Cite

In this study, the model framework that includes almost all relevant parameters of interest has been developed to quantify the electrostatic potential and charge density occurring in microchannels grafted with polyelectrolyte brushes and simultaneously filled with polyelectrolyte dispersion. The brush layer is described by the Alexander-de Gennes model incorporated with the monomer distribution function accompanying the quadratic decay. Each ion concentration due to mobile charges in the bulk and fixed charges in the brush layer can be determined by multi-species ion balance. We solved 2-dimensional Poisson–Nernst–Planck equations adopted for simulating electric field with ion transport in the soft channel, by considering anionic polyelectrolyte of polyacrylic acid (PAA). Remarkable results were obtained regarding the brush height, ionization, electrostatic potential, and charge density profiles with conditions of brush, dispersion, and solution pH. The Donnan potential in the brush channel shows several times higher than the surface potential in the bare channel, whereas it becomes lower with increasing PAA concentration. Our framework is fruitful to provide comparative information regarding electrostatic interaction properties, serving as an important bridge between modeling and experiments, and is possible to couple with governing equations for flow field.

show abstract

Thermo-osmotic transport in nanochannels grafted with pH-responsive polyelectrolyte brushes modelled using augmented strong stretching theory

Abstract: Abstract

Cited by 11 publications

References 89 publications

Analytical solutions for reactive shear dispersion with boundary adsorption and desorption

Analytical solutions for reactive shear dispersion with boundary adsorption and desorption

Structural and electrostatic properties between pH-responsive polyelectrolyte brushes studied by augmented strong stretching theory

Electrostatic Potential Analysis in Polyelectrolyte Brush-Grafted Microchannels Filled with Polyelectrolyte Dispersion

Contact Info

Product

Resources

About