Determination of the spatial distribution of multiple fluid phases in porous media by ultra-small-angle neutron scattering

In the present work contrast-matching USANS (ultra-small-angle neutron scattering) was employed in order to determine the spatial distribution of immiscible fluids confined within a macroporous α-Al2O3 membrane. Water-air as well as water-hydrocarbon and hydrocarbon-air systems were examined and the analysis of the results, also on the basis of a complementary numerical study provided significant information on the behaviour of the multiphase ensemble as it has been demonstrated that the individual fluids occupy certain positions in the pore space, regardless of the actual values of the respective interfacial properties.