Kiel 2011 – scientific programme

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P: Fachverband Plasmaphysik

P 12: Plasmatechnologie I

P 12.4: Talk

Wednesday, March 30, 2011, 11:30–11:45, HS H

Modification of polydimethylsiloxane thin films in H₂ CCRF plasma studied by IR reflection absorption spectroscopy — •Vladimir Danilov, Hans-Erich Wagner, and Jürgen Meichsner — Ernst Moritz Arndt University of Greifswald, Germany

Polydimethylsiloxane (PDMS) thin films (10 nm – 400 nm) were spin-coated on glass substrates covered by aluminium. The plasma treatment was performed in a capacitively coupled radio-frequency (CCRF) discharge comparing the direct plasma contact with that of the plasma radiation. Here, the screening of the thin film from the bulk plasma by selected windows with different cut-off wavelength (soda-lime glass - 300 nm, quartz glass - 160 nm, and MgF₂ - 115 nm) allowed the study of specific spectral ranges. The plasma modification of PDMS thin films was investigated by Fourier-Transform-Infrared-Reflection-Absorption-Spectroscopy (IRRAS). A significant modification effect was observed in experiments with the MgF₂ window, only. This is in agreement with the fact that the H₂ plasma has considerable VUV emission below 170 nm due to the molecular Lyman and Werner band system as well as the Lyman α atomic line. Additionally, the chemical composition along the whole film depth was investigated. It was found that the modified films consist of methyl-free SiO_x top layer (10 – 30 nm), followed by partially demethylated region, and an underlying non-modified PDMS layer in the case of thin films prepared with initial thickness exceeding 350 – 400 nm.

Funded by the Volkswagen Foundation, Plasma Hybrid Coating, grant no. I/83275.