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

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.