Determination of Polyelectrolyte Charge and Interaction with Water Using Dielectric Spectroscopy

Abstract

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.

Charge regularization in phase separating polyelectrolyte solutions

“…[39][40][41][42][44][45][46][47][49][50][51][53][54][55][56] A particular example is the case of aqueous solutions of sodium polystyrene sulfonate containing some divalent salts such as barium chloride. 39,40,47,51,55 The system now becomes more complex with many components: polymer, counterion, cation, and anion of the added salt and solvent.…”

“…There have also been manifestations of the same effect in several other situations involving brushes 24,25 and single chains. 23,[26][27][28][29][30] In addition to these theoretical arguments, computer simulations [31][32][33][34][35][36][37][38] and experiments [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] have shown clearly that the effective charge of the polymer varies as the experimental variables change.…”

Theory of volume transition in polyelectrolyte gels with charge regularization

“…The free energy of the gel phase is similar in form to the free energy of a gel in a salt-free solution and is given by the sum of the same seven contributing factors as given in Eq. (15).…”

“…Numerous experiments, [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] computer simulations, [23][24][25][26][27][28][29][30] and theoretical arguments [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] have established clearly that the effective charge for all polyelectrolyte systems varies as the experimental variables are changed. This effect is known to be present for a variety of polyelectrolyte systems, such as single chains, 32,46 polyelectrolyte brushes, 35 and gels, 36,…”

Ultrashort electric pulse induced changes in cellular dielectric properties

“…1 [10][11][12]. We note that this model has also been referred to as a ''three-shell model'' [13]; however, we follow the two-shell nomenclature Feldman et al TDDS can rapidly obtain dielectric spectra over a wide frequency range with uncertainties on the order 3-5% and 5-7% for the real and imaginary components of the permittivity [14], which are similar to frequency domain systems [15]. We previously used TDDS to study PEF-induced changes in HL-60 suspension conductivity due to single microsecond or nanosecond PEFs [16] and multiple nsPEFs [17].…”