WETTABILITY IMPROVEMENT OF PMMA FILMS WITH HIGH FREQUENCY RF PLASMAS

Abstract

Poly(methyl methacrylate) (PMMA) has a wide variety of applications due to its attractive physical and optical properties. Due to its hydrophobic (water-repellent) character, the surface of PMMA should be modified before being used in applications. In this study, the surface of PMMA films were modified by 40.68 MHz high frequency CCP (capacitive-coupled plasma) RF system with nitrogen (N) and argon (Ar) gases. The experiments carried out under various plasma powers while the pressure and treatment time were kept constant. The wettability of the plasma treated surfaces was analyzed with contact angle and surface free energy (SFE) measurements. Also, the change in the chemical structure of the surfaces was investigated with X-ray photoelectron spectroscopy (XPS). The results showed that all plasma treatments enhanced the hydrophilicity of the surfaces and the lowest contact angle values obtained at high plasma power. The total SFE of the treated surfaces increased with power and the main contribution to total SFE came from polar components. The polar groups formation on the surface after plasma treatment was proved with XPS results. Hence, it was found that high frequency CCP RF plasmas can be used effectively to obtain hydrophilic polymer surfaces.

Keywords

• Surface Engineering
• Plasma Surface Modification
• PMMA
• Wettability
• Polymer

YÜKSEK FREKANSLI RF PLAZMALAR İLE PMMA FİLMLERİNİN ISILABİLİRLİĞİNİN İYİLEŞTİRİLMESİ

Abstract

Poli(metil metakrilat) (PMMA) ilgi çekici fiziksel ve optik özelliklerinden dolayı çok çeşitli uygulamalara sahiptir. PMMA ın hidrofobik (suyu itici) özelliğinden dolayı uygulamalarda kullanılmadan önce yüzeyinin işlenmesi gerekmektedir. Bu çalışmada, PMMA filmlerinin yüzeyleri azot (N) ve argon (Ar) gazları ile 40.68 MHz yüksek frekanslı CCP (kapasitif eşlemeli) RF sistemi kullanılarak işlenmiştir. Deneyler, basınç ve işleme süresi sabit tutularak çeşitli plazma güçlerinde gerçekleştirilmiştir. Plazma uygulanmış yüzeylerin ıslanabilirliği, temas açısı ve yüzey serbest enerji ölçümleri (SFE) ile analiz edilmiştir. Ayrıca X-ışını fotoelektron spektroskopisi (XPS) ile yüzeylerin kimyasal yapısındaki değişim incelenmiştir. Sonuçlar, tüm plazma işlemlerinin yüzeylerin hidrofilikliğini arttırdığını göstermiş ve en düşük temas açı değerleri ise yüksek plazma gücünde elde edilmiştir. İşlenmiş yüzeylerin toplam yüzey serbest enerjisi plazma gücü ile doğru orantılı olarak artmış ve toplam yüzey serbest enerjisine ana katkı polar bileşenden gelmiştir. Plazma ile işleme sonrası yüzeyde oluşan polar grupların varlığı XPS sonuçlarıyla doğrulanmıştır. Böylece yüksek frekanslı CCP RF plazmalarının hidrofilik polimer yüzeyleri elde etme etkin bir şekilde kullanılabileceği bulunmuştur.

Keywords

• Yüzey mühendisliği
• Plazma ile yüzey modifikasyonu
• PMMA
• Islanabilirlik
• Polimer
• Surface engineering
• Plasma surface modification
• Wettability
• Polymer

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