2D material dispersion using a synthetic whiskey: Design of experiment optimization and preliminary application in moisture detection

The present paper deals with the preparation of 2D material dispersions using a mixture of solvents that mimics whiskey. According to the Hansen’s model, we obtained the best solvent applying a design of experiment (DoE) approach to the components present in the whiskey, as reported in literature, in order to obtain a less hazardous and green solvent. The DoE approach was also applied in the exfoliation procedure, in order to maximize the exfoliation and stability of dispersions. We obtained dispersions with a stability lasting longer than nine months in the best case. After the electrical characterization, we deposited the dispersion onto an interdigitated device in order to obtain a moisture sensor. The device showed a sensitivity due to a negative response of sensing (Grotthuss mechanism). The DC characterization showed a good response in the range 50–95% in low voltage regime (up to 3 V). The impedance spectroscopy confirms this hypothesis: the evolution of the Nyquist plot when increasing the relative humidity suggests the intercalation of water molecules among the nanoparticles.