(a) Schematic cross section of the wetting cell system: tuning = Ts-Tr allows control of both bulk solvent evaporation and nanoscale solvent adsorption and desorption from the vapour phase onto the solid substrate. (b) True side section [rotated by ∼90° with respect to (a)] obtained from the drawing axonometric projection. (c) Photograph of the cell assembled and mounted on the sample stage of a synchrotron beamline. (d) Detail of the hermetically sealed NP-solution injection system. (e) X-ray scattering geometry.