### Abstract

The dielectric constant and conductivity of a dilute ensemble of immobile, spherical particles with fixed surface (zeta) potential Φ_{o}, immersed in an electrolytic solution, is obtained in the thin double layer approximation δ≪α, δ being the thickness of the double layer, and α the radius of the particles. Equations of motion for coions and counter-ions are solved by the method of matched asymptotics. The equations of motions, linearized in the applied electric field E_{o} and with coefficients that are functions of the unperturbed potential (zeroth order in E_{o}), are solved to second order in (δ/α). The term giving enhancement in the real part of the effective dielectric constant of the ensemble ε′_{e}, is second order in δ/α; but the series converges if (δ/α)t^{2}/(1-t^{2})≪1, where t = tanh(eΦ_{o}/k_{B}T), e being the ionic charge, k _{B} the Boltzmann constant, and T the absolute temperature. The static value of ε′_{e} to this order, is ε′ _{e}∼36fε′t^{2}/(1-t^{2})^{2}, where f is the volume fraction of particles, ε′ the real part of the dielectric constant of the solution. When Φ_{o}→∞, therefore, t→1, ε′_{e} diverges as ε′ _{e}∼9/4fε′ exp[eΦ_{o}/k_{B}T). The present treatment is free from the approximations of previous analytical results. When applicable, the theory agrees well with experiments over three decades in frequency, with one adjustable parameter Φ_{o}. Comparison with other theories are made.

Original language | English (US) |
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Pages (from-to) | 4683-4693 |

Number of pages | 11 |

Journal | The Journal of Chemical Physics |

Volume | 77 |

Issue number | 9 |

DOIs | |

State | Published - Jan 1 1982 |

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### ASJC Scopus subject areas

- Physics and Astronomy(all)
- Physical and Theoretical Chemistry

### Cite this

*The Journal of Chemical Physics*,

*77*(9), 4683-4693. https://doi.org/10.1063/1.444369

**Dielectric enhancement due to electrochemical double layer : Thin double layer approximation.** / Chew, Weng Cho; Sen, P. N.

Research output: Contribution to journal › Article

*The Journal of Chemical Physics*, vol. 77, no. 9, pp. 4683-4693. https://doi.org/10.1063/1.444369

}

TY - JOUR

T1 - Dielectric enhancement due to electrochemical double layer

T2 - Thin double layer approximation

AU - Chew, Weng Cho

AU - Sen, P. N.

PY - 1982/1/1

Y1 - 1982/1/1

N2 - The dielectric constant and conductivity of a dilute ensemble of immobile, spherical particles with fixed surface (zeta) potential Φo, immersed in an electrolytic solution, is obtained in the thin double layer approximation δ≪α, δ being the thickness of the double layer, and α the radius of the particles. Equations of motion for coions and counter-ions are solved by the method of matched asymptotics. The equations of motions, linearized in the applied electric field Eo and with coefficients that are functions of the unperturbed potential (zeroth order in Eo), are solved to second order in (δ/α). The term giving enhancement in the real part of the effective dielectric constant of the ensemble ε′e, is second order in δ/α; but the series converges if (δ/α)t2/(1-t2)≪1, where t = tanh(eΦo/kBT), e being the ionic charge, k B the Boltzmann constant, and T the absolute temperature. The static value of ε′e to this order, is ε′ e∼36fε′t2/(1-t2)2, where f is the volume fraction of particles, ε′ the real part of the dielectric constant of the solution. When Φo→∞, therefore, t→1, ε′e diverges as ε′ e∼9/4fε′ exp[eΦo/kBT). The present treatment is free from the approximations of previous analytical results. When applicable, the theory agrees well with experiments over three decades in frequency, with one adjustable parameter Φo. Comparison with other theories are made.

AB - The dielectric constant and conductivity of a dilute ensemble of immobile, spherical particles with fixed surface (zeta) potential Φo, immersed in an electrolytic solution, is obtained in the thin double layer approximation δ≪α, δ being the thickness of the double layer, and α the radius of the particles. Equations of motion for coions and counter-ions are solved by the method of matched asymptotics. The equations of motions, linearized in the applied electric field Eo and with coefficients that are functions of the unperturbed potential (zeroth order in Eo), are solved to second order in (δ/α). The term giving enhancement in the real part of the effective dielectric constant of the ensemble ε′e, is second order in δ/α; but the series converges if (δ/α)t2/(1-t2)≪1, where t = tanh(eΦo/kBT), e being the ionic charge, k B the Boltzmann constant, and T the absolute temperature. The static value of ε′e to this order, is ε′ e∼36fε′t2/(1-t2)2, where f is the volume fraction of particles, ε′ the real part of the dielectric constant of the solution. When Φo→∞, therefore, t→1, ε′e diverges as ε′ e∼9/4fε′ exp[eΦo/kBT). The present treatment is free from the approximations of previous analytical results. When applicable, the theory agrees well with experiments over three decades in frequency, with one adjustable parameter Φo. Comparison with other theories are made.

UR - http://www.scopus.com/inward/record.url?scp=0000690705&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000690705&partnerID=8YFLogxK

U2 - 10.1063/1.444369

DO - 10.1063/1.444369

M3 - Article

AN - SCOPUS:0000690705

VL - 77

SP - 4683

EP - 4693

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 9

ER -