Abstract :
[en] We use small-angle neutron scattering (SANS) to investigate the structure and phase behavior of a complex fluid within meso- and macroporous matrices. Specifically, bicontinuous microemulsions of the temperature-dependent ternary system C10E4-water-n-octane are investigated in controlled pore glass (CPG) membranes with nominal pore diameters of 10 nm, 20 nm, 50 nm, and 100 nm. The scattering data were analyzed using the Teubner-Strey model and a multiphase generalization of clipped Gaussian-field models. The analysis indicates changes in the phase structure of the bicontinuous microemulsion in the membranes with the smallest pores. This is attributed to a shift in the ternary phase diagram toward a three-phase structure at lower surfactant concentrations. This effect is likely related to a larger internal surface area in the membranes with smaller pores, which enhances surfactant adsorption onto the pore walls.
Funding text :
The authors thank the Deutsche Forschungs Gesellschaft (DFG) for financial support (project number 455432427). CG is grateful to the F. R. S.-FNRS (Belgium) for a research associate position, and for supporting his contribution to this work through grant P.D.R. T.0100.22. Furthermore, we thank the Institut Laue-Langevin (ILL, Grenoble, France) and the Australian Nuclear and Technology Organisation (ANSTO, Sydney, Australia) for the allocation of beamtime through proposal numbers 9-10-1736 and 16582, respectively. We thank Julian Fischer for the fruitful discussion about the effects of multiple scattering and Dr Henrich Frielinghaus (Forschungszentrum J\u00FClich) for the impact of neutron refraction.
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