USAXS studies of monosaccharide gels. II. The common features of structural changes

The results of SAXS studies are compared for two groups of samples: (i) obtained by in situ process of gelation of Of.-galactose-based gel with benzene as solvent, (it) gels of various concentrations prepared from glucofuranose-based gelator with toluene. The experimental conditions of sample preparation and SAXS measurements were very similar for both groups. The results include fractal analysis of aggregates, and - for aggregate envelopes - the radii of gyration, pair functions, and simulated models. For both groups only two aggregate types were found to be formed: the first - of simple, loose fractal structure and disk-like shape, and the second - smaller aggregates, of well-developed fractal structure and cylinder-like shape. The conditions of the change from the first type to the second one are discussed. In addition, it was verified by the SAXS method on the basis of kind of fractal analysis for the loose structure that the fractal aggregate is built of gelator molecules joined by hydrogen interaction. (c) 2006 Elsevier B.V. All rights reserved.