Electrophoretic Mobility and Electric Conductivity of Salt-Free Suspensions of Charged Soft Particles
A unit cell model is employed to analyze the electrophoresis and electric conduction in a concentrated suspension of spherical charged soft particles (each is a hard core coated with a porous polyelectrolyte layer) in a salt-free medium. The linearized Poisson–Boltzmann equation applicable to a unit...
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| Format: | Article |
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MDPI AG
2021-10-01
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| Series: | Colloids and Interfaces |
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| Online Access: | https://www.mdpi.com/2504-5377/5/4/45 |
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| author | Wei C. Lin Huan J. Keh |
| author_facet | Wei C. Lin Huan J. Keh |
| author_sort | Wei C. Lin |
| collection | DOAJ |
| description | A unit cell model is employed to analyze the electrophoresis and electric conduction in a concentrated suspension of spherical charged soft particles (each is a hard core coated with a porous polyelectrolyte layer) in a salt-free medium. The linearized Poisson–Boltzmann equation applicable to a unit cell is solved for the equilibrium electrostatic potential distribution in the liquid solution containing the counterions only surrounding a soft particle. The counterionic continuity equation and modified Stokes/Brinkman equations are solved for the ionic electrochemical potential energy and fluid velocity distributions, respectively. Closed-form formulas for the electrophoretic mobility of the soft particles and effective electric conductivity of the suspension are derived, and the effect of particle interactions on these transport characteristics is interesting and significant. Same as the case in a suspension containing added electrolytes under the Debye–Hückel approximation, the scaled electrophoretic mobility in a salt-free suspension is an increasing function of the fixed charge density of the soft particles and decreases with increases in the core-to-particle radius ratio, ratio of the particle radius to the permeation length in the porous layer, and particle volume fraction, keeping the other parameters unchanged. The normalized effective electric conductivity of the salt-free suspension also increases with an increase in the fixed charge density and with a decrease in the core-to-particle radius ratio, but is not a monotonic function of the particle volume fraction. |
| first_indexed | 2024-03-10T04:23:23Z |
| format | Article |
| id | doaj.art-f40ad8106ca64ea1bb9c4f81b61b3b11 |
| institution | Directory Open Access Journal |
| issn | 2504-5377 |
| language | English |
| last_indexed | 2024-03-10T04:23:23Z |
| publishDate | 2021-10-01 |
| publisher | MDPI AG |
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| series | Colloids and Interfaces |
| spelling | doaj.art-f40ad8106ca64ea1bb9c4f81b61b3b112023-11-23T07:46:09ZengMDPI AGColloids and Interfaces2504-53772021-10-01544510.3390/colloids5040045Electrophoretic Mobility and Electric Conductivity of Salt-Free Suspensions of Charged Soft ParticlesWei C. Lin0Huan J. Keh1Department of Chemical Engineering, National Taiwan University, Taipei 10617, TaiwanDepartment of Chemical Engineering, National Taiwan University, Taipei 10617, TaiwanA unit cell model is employed to analyze the electrophoresis and electric conduction in a concentrated suspension of spherical charged soft particles (each is a hard core coated with a porous polyelectrolyte layer) in a salt-free medium. The linearized Poisson–Boltzmann equation applicable to a unit cell is solved for the equilibrium electrostatic potential distribution in the liquid solution containing the counterions only surrounding a soft particle. The counterionic continuity equation and modified Stokes/Brinkman equations are solved for the ionic electrochemical potential energy and fluid velocity distributions, respectively. Closed-form formulas for the electrophoretic mobility of the soft particles and effective electric conductivity of the suspension are derived, and the effect of particle interactions on these transport characteristics is interesting and significant. Same as the case in a suspension containing added electrolytes under the Debye–Hückel approximation, the scaled electrophoretic mobility in a salt-free suspension is an increasing function of the fixed charge density of the soft particles and decreases with increases in the core-to-particle radius ratio, ratio of the particle radius to the permeation length in the porous layer, and particle volume fraction, keeping the other parameters unchanged. The normalized effective electric conductivity of the salt-free suspension also increases with an increase in the fixed charge density and with a decrease in the core-to-particle radius ratio, but is not a monotonic function of the particle volume fraction.https://www.mdpi.com/2504-5377/5/4/45electrophoresiselectric conductioncharged soft spheresalt-free solutionparticle concentration effect |
| spellingShingle | Wei C. Lin Huan J. Keh Electrophoretic Mobility and Electric Conductivity of Salt-Free Suspensions of Charged Soft Particles Colloids and Interfaces electrophoresis electric conduction charged soft sphere salt-free solution particle concentration effect |
| title | Electrophoretic Mobility and Electric Conductivity of Salt-Free Suspensions of Charged Soft Particles |
| title_full | Electrophoretic Mobility and Electric Conductivity of Salt-Free Suspensions of Charged Soft Particles |
| title_fullStr | Electrophoretic Mobility and Electric Conductivity of Salt-Free Suspensions of Charged Soft Particles |
| title_full_unstemmed | Electrophoretic Mobility and Electric Conductivity of Salt-Free Suspensions of Charged Soft Particles |
| title_short | Electrophoretic Mobility and Electric Conductivity of Salt-Free Suspensions of Charged Soft Particles |
| title_sort | electrophoretic mobility and electric conductivity of salt free suspensions of charged soft particles |
| topic | electrophoresis electric conduction charged soft sphere salt-free solution particle concentration effect |
| url | https://www.mdpi.com/2504-5377/5/4/45 |
| work_keys_str_mv | AT weiclin electrophoreticmobilityandelectricconductivityofsaltfreesuspensionsofchargedsoftparticles AT huanjkeh electrophoreticmobilityandelectricconductivityofsaltfreesuspensionsofchargedsoftparticles |