Electrical conductivity of some cationic polysaccharides. I. Effects of polyelectrolyte concentration, charge density, substituent at the ionic group, and solvent polarity

Abstract

Electrolytic conductivity behavior of some cationic polysaccharides in water, methanol, and the mixtures water/methanol is presented. The polyelectrolytes investigated contain quaternary ammonium salt groups, N‐alkyl‐N,N‐dimethyl‐2‐hydroxypropyleneammonium chloride, attached to a dextran backbone. This study considers the influences of polymer concentration (1 × 10−6 < C < 1 × 10−2 monomol L−1) and the charge density (ξ = 0.48–3.17) modified either by changing charge distance (b) or dielectric constant of the solvent (ε) on polyion–counterion interaction in salt‐free solutions. Above the critical value, ξc = 1, the variation of the equivalent conductivity (Λ) as a function of concentration is typical for a polyelectrolyte behavior. The conductometric data in water were analyzed in terms of the Manning's counterion condensation theory. The presence of longer alkyl chains at quaternary N atoms was found to have a negligible influence on the Λ values. The results show that the decrease of the medium polarity results in the decrease of the number of free ions and, consequently, of the equivalent conductivity values. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3584–3590, 2005

Transport properties of some cationic polysaccharides

“…This study was stimulated by the increasing attention paid nowadays to the study of the behavior of ionic polysaccharides in solution, taking into account their involvement in many processes in molecular biology [32]. The previous physicochemical studies on some of these cationic polysaccharides under study (i.e., fluorescence, viscometry and microcalorimetric titration and conductometry), mainly focused on their self-aggregation in water, revealed a complex picture of the competition between the electrostatic and hydrophobic interactions [33][34][35]. By changing the charge density, a fine tunning of the electrostatic polyion-counterion interactions, and hence of the viscometric and conductometric properties of these systems with a very well established and controllable structure, can be obtained.…”

Functional Polymers Based on Dextran

“…The micelles with dodecyl-and cetyl alkyl side groups are formed mainly intramolecularly, whereas octyl side groups lead to intra-and intermolecular interactions. The association of hydrophobically modified polycationic dextran derivatives with oppositely charged surfactants like sodium octyl, dodecyl and tetradecyl sulfate leads to aqueous solutions with complex phase behaviour and self-assembling morphologies in solution [247][248][249][250]. These properties, e.g.…”

Cationization of polysaccharides: A path to greener derivatives with many industrial applications

“…These polysaccharides effectively interacted with biological surfactants such as biliar salts, and thus presented potentiality as hipocolesteremic agents [77,81]. The cationized polysaccharides also interacted with different sodium alkyl sulfates [79,[82][83][84], and with cationic surfactants [85]; the electrical conductivity and viscosity properties in different solvents [86][87][88][89][90][91], the thermodinamic interaction with water [92], as well as their applications in clay flocculation were evaluated [93][94][95]. The interaction between hydrophobically modified cationic polysaccharides based on dextran and a flavonoid drug (rutin) was studied in view of drug delivery applications [80].…”