Candle soot as a template for fabricating superhydrophobic titanium dioxide film by magnetron sputtering

A superhydrophobic titanium dioxide (TiO2) film with the template of a candle smoked Si wafer was successfully fabricated by magnetron sputtering. The film specimens were examined by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, contact angle meter, scanning electron microscope (SEM), transmission electron microscope (TEM) and gas-sensitivity tests. The results showed that the TiO2 solely deposited on the silicon wafer was hydrophilic, with its contact angel only 61, while it became superhydrophobic with water contact angle up to 155 after depositing on candle smoked substrate. The SEM and TEM results showed that the TiO2 morphology kept the spongy-like framework covering on the carbon clusters formed template. In this paper, the superhydrophobic TiO2 was achieved on the candle soot without modification by low surface energy materials, which shows the dominance of the structure for preparing hydrophobic TiO2 films. The TiO2 films deposited on the candle soot more excellent gas sensitivity than pure TiO2 films.