Fabrication of superhydrophobic thin films on various substrates using SiO2 nanoparticles coated with polydimethylsiloxane: towards the development of shielding layers for gas sensors

Abstract

Superhydrophobic membranes with high gas permeability were prepared and characterized. Materials such as a metal mesh, paper, fabric and polytetrafluoroethylene were dip-coated in a hexane-based solution of SiO₂ nanoparticles coated with polydimethylsiloxane (PDMS). The dip-coating provided a superhydrophobic characteristic to the surfaces of our membranes with water contact angles exceeding 160°. On the other hand, a high membrane permeability of CO₂ and dimethyl methylphosphonate vapor were obtained, indicating that our preparation method is useful for the fabrication of gas sensor shielding layers that allow selective permeation of gas vapors from gas/aqueous-liquids mixtures.