Simple and reproducible method of preparing transparent superhydrophobic glass

We demonstrate a silanization reaction-based simple and reproducible method of converting a standard microscope glass slide to a transparent superhydrophobic surface with careful controlling of the temperature, concentration, and reaction time. By optimizing the preparation conditions, the two step treatment of a glass slide (reaction with dilute methyltrichlorosilane in toluene followed by ethanol extraction) leads to ultrahigh water contact angles (> 150°), i.e., water droplets sit atop the surface in the Cassie–Baxter state while the glass slide is still optically transparent. UV–vis absorption spectra confirm that the optical transmittance of the superhydrophobic glass slides can be as high as 99% (λ = 550 nm), which is superior to untreated slides (93%). Both the superhydrophobicity and optical transparency are dictated by the microscopic morphology resulting from the controlled silanization of the glass surface, for which in this study the reproducibility was achieved to be about 90%.

► Simple silanization reaction creates superhydrophobic glass surface reproducibly.
► The superhydrophobic glass slide retains its optical transparency.
► Enhanced hydrophobicity/transparency dictated by the nanostructured morphology.