J. Phys. II France
Volume 4, Numéro 6, June 1994
Page(s) 1001 - 1019
DOI: 10.1051/jp2:1994180
J. Phys. II France 4 (1994) 1001-1019

Further evidence of liquid-like correlations in polyelectrolyte solutions

Isabelle Morfin, Wayne F. Reed, Marguerite Rinaudo and Redouane Borsali

CERMAV-CNRS and University Joseph Fourier, P.O. Box 53, 38041 Grenoble Cedex 9, France

(Received 29 June 1993, revised 21 February 1994, accepted 3 March 1994)

Elastic, quasi elastic light scattering and viscosity experiments were used to investigate polyelectrolytic polysaccharide succinoglycan solutions at low solute concentration $C_{\rm p}$, and salt concentration $C_{\rm s}$. The highest degree of "organization" in the solution necessary to describe the observations is a simple liquid type correlation, manifested by broad angular static and dynamic scattering maxima of visible light for solutions at very low ionic strength. Letting the solutions stand undisturbed for a few days did not lead to a sharpening of the broad maxima, nor did lowering the temperature. The positions of these maxima scale roughly as $C^{1/2}_{\rm p}$. By adding salt, the maxima were found to maintain roughly the same position. The reciprocal diffusion coefficient D-1(q) corresponding to the liquid-like correlation state followed the intensity maxima, as has often been demonstrated for similar systems. No "slow mode" or "extraordinary regime" of diffusion was found associated with the static and dynamic light scattering maxima although extreme care in filtration of solution was necessary to avoid a spurious slow diffusional mode due to aggregates.

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