Crossover behavior in high-frequency dielectric relaxation of linear polyions in dilute and semidilute solutions

Ito, Kohzo; Yagi, Akira; Ookubo, Norio; Hayakawa, Ritsuko

doi:10.1021/ma00205a027

Cited by 84 publications

(178 citation statements)

References 11 publications

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“…This temperature normalization is very good for each of the four polyions, supporting the premise of Ito et al 12 that the intermediate relaxation corresponds to motion of free counterions. The relaxation time also qualitatively obeys the τ ion ∼ c -1 scaling expected by eq 5, but there are distinct quantitative discrepancies that will lead to concentration dependences of f and τ discussed below.…”

Section: Methodssupporting

confidence: 80%

Determination of Polyelectrolyte Charge and Interaction with Water Using Dielectric Spectroscopy

Bordi¹,

Cametti²,

Tan³

et al. 2002

Macromolecules

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Using the dielectric strength and relaxation time of a high-frequency (1 MHz-1 GHz) dielectric relaxation, we estimate the effective charge on polyelectrolytes and their net thermodynamic repulsive interaction with solvent. The utility of this method is demonstrated for semidilute aqueous solutions of the sodium salt of several sulfonated polyelectrolytes of varying charge and strength of repulsive interaction with water, with no added salt. At high concentrations, as the concentration is increased, the effective charge of strongly charged polyelectrolytes always increases, as previously observed in conductivity and osmotic pressure measurements. Interestingly, we find that the effective polymersolvent repulsion increases in direct proportion to the effective charge on the polyelectrolyte chains. This proportionality means that, although the additional charge would increase the contour length of the chain of electrostatic blobs, the increase in repulsion between solvent and polymer offsets this effect, making the contour length of the chain essentially independent of polyelectrolyte concentration. This then explains why the correlation length of semidilute polyelectrolyte solutions fortuitously agrees with simple scaling predictions.

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Section: Methodssupporting

confidence: 80%

Determination of Polyelectrolyte Charge and Interaction with Water Using Dielectric Spectroscopy

Bordi¹,

Cametti²,

Tan³

et al. 2002

Macromolecules

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show abstract

“…First of all, at the polymer concentration investigated, from 0.5 up to 10 mg/mL, the system is in a semidilute or concentrated regime, that is, polymer-polymer interactions cannot be neglected. This emerges from the dielectric behavior of the polymer solutions and in particular from the high-frequency dielectric dispersions whose parameters (the dielectric increment and the relaxation time) follow exactly the dependence on the polymer concentration suggested by Ito et al 20 for the crossover region from dilute to semidilute or concentrated regime. These aspects have been extensively investigated by the prsent authors elsewhere.…”

Section: Introductionsupporting

confidence: 60%

Conformational Changes of Xanthan in Salt-Free Aqueous Solutions: A Low-Frequency Electrical Conductivity Study

1996

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The low-frequency electrical conductivity of xanthan in salt-free aqueous solutions has been measured in a wide temperature range, from 5 to 70°C, covering the interval where a thermal-induced conformational transition in the polymer chain occurs. The polymer concentration has been varied up to 10 mg/mL, from the semidilute region, where polymer chains are partially entangled with each other, to the concentrated region. Deviations from the dilute regime and the conformation of the polyion in a double-stranded helix with a finite radius make the counterion condensation of the Manning model for highly charged polyelectrolytes inapplicable. On the other hand, on the basis of the present conductivity data and of our previous measurements of radiowave dielectric relaxations of the same polymer solution (J. Phys. Chem. 1995, 99, 274) we find that a fraction of counterions, although different from that predicted by Manning, will condense, altering the value of the conductivity of the whole solution. This condensation is largely independent of the polymer chain structure and, to a first approximation, of polyion concentration, the fraction of free counterions assuming a value that increases with temperature from about f ) 0.53 at 20°C to about f ) 0.75 at 70°C. With these values and considering an appropriate conductivity expression consisting of additive contributions, i.e., polyion and free counterions, according to the suggestions of the Manning theory, a reasonable agreement with the experimental data can be found.

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“…25 Ito et al found that the dielectric parameters show scaling behavior with concentration, 26 and Rubinstein et al reviewed later the scaling theory of polyelectrolyte solution. 27 Though considerable theoretical work has been devoted to polyelectrolyte solution, the experimental data is relatively backward.…”

Section: Introductionmentioning

confidence: 99%

Effects of Concentration and Temperature on the Dynamic Behavior of PAA-g-PEO Aqueous Solutions with Different Counterion Species: A Dielectric Spectroscopy Study

Liu

Zhao

2012

J. Phys. Chem. B

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Dielectric properties of PAA-g-PEO-7% solutions with different counterions were measured as a function of concentration and temperature over a frequency range of 40 Hz to 110 MHz. After the contribution of electrode polarization effects was subtracted, the dielectric spectra of PAA-g-PEO-7% solutions showed three relaxation processes in the experimental frequency range, named low-, mid-, and high-frequency relaxation. The observed three relaxations were strictly analyzed by using the Cole-Cole relaxation function, and the dielectric parameters (dielectric increment Δε and the relaxation time τ) were obtained. The scaling relation of dielectric increment and relaxation time of high frequency with concentration C(p) were obtained and compared with the predictions of scaling theories. The information on the dynamics and microstructure of PAA-g-PEO-7% was obtained. Using different counterion species, the mid- and high-frequency relaxation mechanisms were attributed to the fluctuation of condensed counterions and free counterions, respectively, and the low-frequency relaxation was considered to be caused by the interface polarization of a complex formed by the hydrogen bonding between carboxylic group of PAA and ether oxygen on the side-chain PEO. In addition, by means of Eyring equation, the thermodynamic parameters, enthalpy change ΔH and entropy change ΔS, of the three relaxations were calculated from the relaxation time and discussed from the microscopic thermodynamical view.

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Crossover behavior in high-frequency dielectric relaxation of linear polyions in dilute and semidilute solutions

Cited by 84 publications

References 11 publications

Determination of Polyelectrolyte Charge and Interaction with Water Using Dielectric Spectroscopy

Determination of Polyelectrolyte Charge and Interaction with Water Using Dielectric Spectroscopy

Conformational Changes of Xanthan in Salt-Free Aqueous Solutions: A Low-Frequency Electrical Conductivity Study

Effects of Concentration and Temperature on the Dynamic Behavior of PAA-g-PEO Aqueous Solutions with Different Counterion Species: A Dielectric Spectroscopy Study

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