Application of electrostatic persistence length to polyelectrolyte solutions

Abstract

The effects of added simple salt and polyion charge on the chain flexibility of an alternating copolymer of isobutyl vinyl ether and maleic acid are analyzed. The persistence length of this polymer in aqueous NaCl solution is calculated from sedimentation and viscosity data on the basis of a worm-like chain model. It is found that this polymer is in the state of a highly expanded conformation at low ionic strength, exhibiting a semi-rigid macromolecular behaviour and that it behaves like a rather coiled polymer with small persistence length at high salt concentration. The electrostatic persistence length calculated from the theory of Fixman et al. shows a 1 /l/Fs-dependence on added salt concentration C, .

Comparison of experimental and theoretical persistence length of some polyelectrolytes at various ionic strengths

“…This treatment was recently applied to po-lyamides11 and cellulose derivatives12 and also to polyelectrolytes at various ionic strengths: sodium polyacrylate (PAANa),13 sodium poly[((acrylamido)methyl)propanesulfonate] (PAMPSNa),14 and the sodium salt of an alternating copolymer of isobutyl vinyl ether and maleic anhydride (PBVMANa) at various degrees of neutralization. 15 For the PAMPSNa, the experimental persistence length value q, obtained from viscosity data, is in fairly good agreement with that estimated according to Benoit and Doty16 from the radius of gyration measured by light scattering. For PAANa and PBVMANa, the persistence length has been found to depend linearly upon the inverse of the root square of the ionic strength in the range 0.01-1.0 M. The determination of the viscosity of polyelectrolytes has always appeared to be very difficult at low ionic strength, owing to the expansion of the polyions as the ionic strength and/or the concentration decreases.…”

Effects of Polyelectrolyte Chain Stiffness, Charge Mobility, and Charge Sequences on Binding to Proteins and Micelles

“…b At I = 1.5 M , d From ref e Based on extrapolation of l p vs (κ -1 / d ) to (κ -1 / d ) = 0, where d is equal to the polyelectrolyte charge spacing. , f Obtained at I = 0.5 M ( d /κ -1 > 1) …”

Investigation of zeolites by photoelectron and ion scattering spectroscopy Part IV XPS studies of vanadium-modified zeolites

“…liquid-phase oxidation of phenol or toluene by oxidation of butadiene,2 epoxidation of H 2 O 2 ,1 unsaturated alcohols, aldehydes and chlorides with H 2 O 2 ,3 ammoxidation of p-and m-xylenes to aromatic nitriles,4 oxidation of naphthalene (over the large-pore molecular sieve V-NCL-A5), and reduction of NO with both in the NH 3 , absence and the presence of oxygen.6h9 Such catalysts have been prepared with the intention of producing both intraframework vanadium (VS-1, VS-210h12) and intra-zeolite vanadium oxide dispersions.1,13 In addition, the exchange of vanadyl cations (VO2`) into zeolites of Y, MFI and other types has been reported. 6,14,15 The identiÐcation of the actual vanadium structures present after preparation or catalysis is of prime importance for the assay of the quality of synthesised products, as well as for the elucidation of active species in catalysis by vanadium-modiÐed zeolites.…”