Fabrication of superhydrophobic surface using one-step chemical treatment

The fabrication techniques of hydrophobic and superhydrophobic surfaces have received attention from many researchers. In this study, the change of water contact angle of the glass surface modified with chlorosilane or trichlorosilane compound was investigated. The microscope glass with water contact angle of 88° and 107° were obtained by treating with trimethylchlorosilane (TMCS) and octadecyltrichlorosilane (OTS), respectively. The chemical resistance of hydrophobic layer was evaluated by immersing the treated samples into an acidic or a basic solution. The result showed that OTS bonded to the glass surface more strongly than TMCS. The superhydrophobic state with the highest contact angle of 154° (sliding angle 17°) could be achieved with the glass microfiber filter by using OTS. The similar phenomenon could not be observed with TMCS because the TMCS-treated glass filter remained completely wetted with all investigated concentrations. The hydrophobic layer on the glass slides was strongly affected by abrasive force while the contact angle value of more than 154° was detected in the treated glass filter after 50 cycles of abrasion test on a sandpaper. The scanning electron microscope (SEM) images had revealed the aggregation of the OTS molecules on the glass filter surface. The chemically-treated filter performed both superhydrophobic and superoleophilic properties. The OTS coating showed strong resistance to the organic solvent. Separation of mixture n-hexane and water was successfully demonstrated using the modified filter.