The interaction between water in materials and external humidity dictates a wide range or natural and technological processes (e.g. plant physiology, water harvesting/purification strategies, energy transport/storage, construction materials, soil science, etc.). We are interested in synthetic micro/nano-fluidic systems where the water content and transport dynamics are controlled by external changes in humidity. One way to obtain spontaneous filling/emptying of water is to combine confinement and solute-induced effects. The internship aims at characterizing the filling/emptying response of micro and nanochannels containing salt solutions to humidity changes, and to characterize how the competition between various effects (capillarity, osmosis, phase change: evaporation, condensation, crystallization, deliquescence, etc.) dictate the phase diagram of filling state as a function of humidity, and the dynamics of these processes. Interestingly, the results of these fundamental investigations can be directly transferred in an ongoing European project aiming at harvesting electrical energy from natural from natural or industrial humidity cycles.