Relaxation and electrophoretic effects in polyelectrolyte solutions. II. Polyelectrolyteplus‐salt solutions

Abstract

SynopsisElectrophoretic mobilities are studied in polyelectrolyte-plus-salt solutions, using linear irreversible thermodynamics and the concepts of relaxation and electrophoretic effects discussed in paper I. If ionic interactions are treated within the Debye-Huckel approximation, co-ions contribute significantly to the relaxation field experienced by polyions. Moreover, through self-diffusion and electrophoretic measurements, the effective valence of the polyion becomes an experimentally accessible parameter. It should provide another method to check the concept of ion condensation.

Collapse of Linear Polyelectrolyte Chains in a Poor Solvent: When Does a Collapsing Polyelectrolyte Collect its Counterions?

“…Following the general conductivity theory based on nonequilibrium thermodynamics, [48][49][50][51][52] and ignoring interionic friction effects, the electrolytic conductivity of a polyelectrolyte solution in the presence of added salt, σ, is given by…”

“…Following the general conductivity theory based on nonequilibrium thermodynamics, − and ignoring interionic friction effects, the electrolytic conductivity of a polyelectrolyte solution in the presence of added salt, σ, is given by σ = σ s + γ false( λ Br + λ poly false) c p ′ where σ s represents the conductivity of the bare salt solution (in S/cm), λ Br and λ poly are the equivalent electrophoretic mobilities (in S cm 2 /equiv) of the bromide ion and the polyion, respectively and c p ′ is the equivalent concentration of the polyelectrolyte (in equiv/L). The equivalent conductivity of a polyelectrolyte solution, Λ = (σ − σ s )/ c p ′ may then be expressed as Λ = γ false( λ Br + λ poly false) …”

Dielectric spectroscopy and conductivity of polyelectrolyte solutions

“…A polyion in dilute solution is surrounded by an oppositely charged atmosphere whose spatial distribution is distorted and becomes asymmetric in the presence of an external electric field. As a consequence, in calculating the electrophoretic coefficient, the effect of the resulting 'asymmetry field' must be summed up to the external electric field effect [160,161].…”

“…The 'structural unit'that should be used in calculating the friction coefficient (equation ( 74)) is the correlation blob. Taking into account the asymmetry field effect [122,160,161], the friction coefficient for a random coil [163] of N/g statistical units of length ξ is given by…”

Capillary Electrophoresis Measurements of the Free Solution Mobility for Several Model Polyelectrolyte Systems

“…Additional theories for polyelectrolyte electrophoresis have been developed by Hermans and Fujita , (porous sphere model), Overbeek and Stigter (porous sphere model), Takahashi et al (Poisson−Boltzmann rod model without relaxation effects), Abramson et al (Debye−Hückel rod model with incorrect orientational averaging), Mills (Poisson−Boltzmann rod model with incorrect orientational averaging and no relaxation effects), Imai and Iwasa (free-draining Poisson−Boltzmann coil model with unspecified chain friction constant), Schmitt et al , (phenomenological Debye−Hückel theory invoking empirical binary friction coefficients), van der Drift et al (Poisson−Boltzmann rod model with semiempirical relaxation correction), Long et al , (Zimm model with localized forces and no relaxation correction), and Allison et al ,, (boundary element methodology to describe the hydrodynamics and Poisson−Boltzmann electrostatics of arbitrarily shaped and charged rigid polyions).…”