Development of superhydrophobic surface on glass substrate by multi-step atmospheric pressure plasma treatment

• Development of rapid and simple method for superhydrophobic surface
• Effects of atmospheric pressure plasma for superhydrophobic surface preparation
• Observation of chemical and physical surface modification by atmospheric pressure plasma
• Effects of substrate properties for plasma–surface interaction

Superhydrophobic surface was prepared on a glass by helium based CH4 and C4F8 atmospheric pressure plasmas, and its water wettability was investigated by a water droplet contact angle method. The water droplet spread over on the untreated glasses that showed the initial hydrophilic property of the glass surface. Then, the static contact angles became about 85° and 98° after a single step CH4 plasma treatment and a single step C4F8 plasma treatment, respectively. The contact angle was remarkably increased to 152°, indicating a superhydrophobic property, after a sequential multi-step CH4 and C4F8 plasma treatment. From the X-ray photoelectron spectroscopy and the field emission scanning electron microscope measurements, it was found that the physical morphologies and the chemical compositions were depending on the substrate materials, which were important factors for the superhydrophobicity.