Electrostatic polyelectrolyte complexes: thermodynamic assembly properties

Polysaccharides are common ingredients in medical, technological and industrial products. In many formulations, the oppositely charged polysaccharides (two major biopolymers) are used simultaneously. Understanding their interactions can help control physical properties and stability of formulating. The excess conductivity, sigma(E), and excess energy of activation (Delta Epsilon(sigma))(Epsilon) of electrical conductivity have been investigated by using electrical conductivities measurements for solution of Sodium carboxymethylcellulose (CMC) + solution of chitosan (CH) mixtures over the entire range of volumes fractions X-1 of CMC for three different temperatures. This system exhibited a very large negative value of sigma(E) and very large positive values (Delta Epsilon(sigma))(Epsilon) due to increased hydrogen bonding interactions and correlation length between unlike molecules in the two critical regions, and very large differences between the pure components. The activations parameters Delta Eta(sigma) and Delta S-sigma have been also calculated, and show that the two critical regions have an important effect on the electrical conductivity properties. In this study, (Delta H-sigma)(phi 1), (Delta H-sigma)(phi 1)(subset of), (Delta H-sigma)(phi 2), (Delta H-sigma)(phi 2)(subset of), X-phi 1, X-phi 1, X-phi 1(subset of) and X-phi 2(subset of) were identified. [GRAPHICS] .