フッ素系樹脂薄膜の大気圧プラズマ処理と表面微細構造の形成メカニズム

抄録

This paper describes fabrication of a nano-textured surface on a fluorocarbon thin film using atmospheric-pressure microplasma (μ-AP; NU-Eco Engineering). Results show that a textured surface with vertical bumps of several tens of nanometers can be fabricated on a fluorocarbon 1.0-μm-thick thin film coated onto a steel substrate when argon gas is supplied with a 4.0 dm³ min⁻¹ flow rate. The plasma-treated surface roughness decreased concomitantly with increased processing distance. Moreover, the horizontal intervals of the bumps are influenced by annealing treatment conditions.
From measurement results obtained using atomic force microscopy (AFM), results show that non-uniformity of fluorocarbon polymer orientation, which is detectable as fluctuations in friction force, in the coating film before the plasma treatment is correlated with the number density of bumps fabricated by the plasma treatment, indicating that well-oriented fluorocarbon polymers are difficult to etch using plasma treatment. Furthermore, chemical bond components of C1s were analyzed using X-ray photoelectron spectroscopy (XPS) before and after treatment. Results show that C-H and C-C bonds are fewer after the plasma treatment, but C-O and C=O bonds are more numerous. The oil contact angles changed concomitantly with the change in surface morphology and chemical bond components according to the plasma treatment.