Nonisothermal effects on water potential measurement in a simple geometry

In nature, unsaturated porous media, like soils or plant tissues, are often submitted to temperature gradients which can trigger water transport. A nanofluidic tool is employed here to measure the changes in water potential in response to temperature variations in a model geometry. Variations of -7.9 MPa/K are observed in agreement with previous measurements but which differ from a simple modeling, pointing at subtle couplings between natural convection and the Soret effect at play in the setup.