Preparation of super-hydrophilic amorphous titanium dioxide thin film via PECVD process and its application to dehumidifying heat exchangers

The super-hydrophilic amorphous titanium dioxide (TiO2) thin film was prepared by plasma-enhanced chemical vapor deposition (PECVD) process for an application to dehumidifying finned-tube heat exchangers. The chemical components and surface structure were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscope (SEM). The wettability and long-term durability were investigated by measuring the water contact angle and by performing wet/dry cycles. The samples were subjected to 1000 times of wet/dry cycles to establish long-term durability. The water contact angle of the amorphous TiO2 thin film was about 8° at as-deposited film with O2 plasma treatment and was about 15° after 1000 wet/dry cycles. The amorphous TiO2 thin film had excellent wettability and long-term durability under full wetting conditions.