Rheology of sphingans in EPS-surfactant systems

Moritz Gansbiller; Jochen Schmid; Volker Sieber

doi:10.1016/j.carbpol.2020.116778

Rheology of sphingans in EPS-surfactant systems

Carbohydr Polym. 2020 Nov 15:248:116778. doi: 10.1016/j.carbpol.2020.116778. Epub 2020 Jul 17.

Authors

Moritz Gansbiller¹, Jochen Schmid², Volker Sieber³

Affiliations

¹ Chair of Chemistry of Biogenic Resources, Technical University of Munich, Campus for Biotechnology and Sustainability, Schulgasse 16, 94315, Straubing, Germany. Electronic address: m.gansbiller@tum.de.
² Chair of Chemistry of Biogenic Resources, Technical University of Munich, Campus for Biotechnology and Sustainability, Schulgasse 16, 94315, Straubing, Germany; Norwegian University of Science and Technology, Department of Biotechnology and Food Science, Sem Sælands vei 6-8, 7491, Trondheim, Norway. Electronic address: jochen.schmid@ntnu.no.
³ Chair of Chemistry of Biogenic Resources, Technical University of Munich, Campus for Biotechnology and Sustainability, Schulgasse 16, 94315, Straubing, Germany; Fraunhofer IGB, Straubing Branch BioCat, Schulgasse 23, 94315, Straubing, Germany; TUM Catalysis Research Center, Ernst-Otto-Fischer-Straße 1, 85748, Garching, Germany; The University of Queensland, School of Chemistry and Molecular Biosciences, 68 Copper Road, St. Lucia, 4072, Australia. Electronic address: sieber@tum.de.

PMID: 32919568
DOI: 10.1016/j.carbpol.2020.116778

Abstract

A model-based rheological characterization of four sphingans in combination with four prominent surfactants of cosmetic formulations of cationic, anionic, zwitterionic and neutral headgroup characteristics was performed. The impact of the surfactants on the rheological properties, based on changes in the mechanical models was evaluated in respect to the closely related structural differences of the polysaccharides, to give an insight on the structure-function relationship of these interactions. The side chains of the sphingans Welan, Diutan and S-88 seem to be involved in the masking of the anionic charge of the polysaccharide backbone, making them highly compatible even with cationic surfactants. The effect of a disaccharide side chain of Diutan also impacts its intermolecular interactions opposed to Welan and S-88, resulting in different surfactant interactions as well as temperature stability. The lack of a side chain in Gellan leads to large incompatibilities with zwitterionic and cationic surfactants due to high polysaccharide-surfactant interactions.

Keywords: Burgers model; EPS–surfactant mixtures; Maxwell model; Mechanical rheological models; Sphingans; Surfactants.