Hexamethyldisiloxane coating by plasma to create a superhydrophobic surface for fabric masks

This study evaluated the effect of hexamethyldisiloxane (HMDSO) plasma on the fabrics surface to produce masks. Samples of 400-thread count cotton fabric were used. The fabrics was covered with a layer of HMDSO employing plasma enhanced chemical vapor deposition. Optical Microscopy, helium ion beam microscopy (HIM) and atomic force microscopy (AFM) were used for topographic analysis. Fourier transformed infrared spectroscopy technique was used to analyze the chemical modifications on surface. The level of hydrophobicity was evaluated using contact angle measurements. To evaluate the effect of washing cycle on the plasma coating, a protocol proposed by the World Health Organization was used. All experiments were performed in triplicate. For the statistical analysis, the Mann–Whitney, Kruskal–Wallis and Dunn tests were used. AFM showed that, after HMDSO plasma coating, a layer of small granules agglomerated on the original surface of the fabric was visualized. The fabric, which initially had a 0° contact angle value, presented angles of 120° after the plasma coating. It was concluded that the use of cotton fabric coated with HMDSO plasma proved to be adequate for the manufacture of protective masks, since the coating made the surface hydrophobic and this property is maintained even after washing cycles.