Structure and molecular mobility of complexes between carboxymethylpolysaccharides (carboxymethylcellulose and carboxymethylchitin) and alkaline-earth metal ions in aqueous systems were studied by means of dynamic viscoelasticity, SAXS and NMR measurements. The frequency-dependent curves of the dynamic modulus measured with a coneplate rheometer shift to a longer time-scale region with complex formation and can be superposed to a master curve by only a horizontal shift. This means that the

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... ation times lengthen by complexation and that the complexation is an intramolecular rather than an intermolecular process. The SAXS and NMR measurements revealed that the site for complexation is a cavity between the carboxyl group and the hydroxy group attached to the neighbouring residue. A new molecular model for complexation was presented.