MEASUREMENT OF THE CHEMICAL POTENTIAL OF A LIQUID IN POROUS MEDIA

This study deals with experimental methods dedicated to the determination of the liquid chemical potential in heterogeneous media. Various measurement techniques are proposed, including anew mechanical method based on the expansion of the air-vapor atmosphere surrounding a sample. From the large range of materials under investigation (soil, wood, gel, agroproduct, biological tissue), various microstructures are investigated. Thus liquid-solid interactions occurring at the interface scale involve several physicochemical phenomena that can all be interpreted through the concept of chemical potential. The dependence of the liquid chemical potential on the liquid content is established over the whole range of energy. Eventually, extrapolation of the results toward the low values of chemical potential is analyzed, and a modeling approach is proposed. Even if the results presented concern essentially a water phase, the principles are applicable to several other fluids.