Bicelle-Bicelle lamellar stacking of a fatty alcohol and a C8–10 alkyl PolyGlycoside surfactant

Bio-based surfactants, such as alkyl polyglucosides (APG), exhibit non-classical surfactant behavior due to their sugar-based hydrophilic head groups. The self-assembly behavior of Triton CG110 (C8 alkyl chain APG) was examined in the presence and absence of 1-dodecanol (C12OH) using small-angle X-ray and neutron scattering (SAXS and SANS). These techniques allowed for the characterization of aggregate structures and the determination of phase transitions as a function of surfactant concentration and composition. SAXS and SANS analyses revealed that Triton CG110 alone forms bicelles in water. Upon addition of C12OH, mixed bicelles were observed at low concentrations, indicating co-assembly of the two surfactants. At higher surfactant concentrations, maintaining a fixed Triton CG110:C12OH ratio, a bicelle-to-lamellar transition occurred due to bicelle stacking, while the common lamellar packing adopts a mixed lamellar stacking, where different molecules integrate within the lamellar arrangement. These structural transitions explain the observed non-linear rheological behavior and suggest potential applications for Triton CG110 in systems requiring tailored mesophase structures.