Stability of trimethylsilyl acetate-based plasma polymers towards atmospheric and water environments. (August 2021)

• Record Type: Journal Article
• Authors: Kelarová, Štěpánka; Stupavská, Monika; Homola, Vojtěch; Přibyl, Roman; Zábranský, Lukáš; Campbell, Anna Charvátová; Havlíček, Marek; Václavik, Richard; Buršíková, Vilma
• Is Part Of: Polymer degradation and stability. Volume 190(2021)
• Publication Date: 2021-08
• Subjects: Trimethylsilyl acetate -- PECVD -- XPS -- AFM -- FTIR -- Hydrophobicity -- Degradation; Polymers -- Deterioration -- Periodicals; Stabilizing agents -- Periodicals; Polymères -- Dégradation -- Périodiques; Stabilisants -- Périodiques; 668.9
• DOI: 10.1016/j.polymdegradstab.2021.109628
• Languages: English
• ISSNs: 0141-3910

Abstract

Highlights: Plasma polymerization of trimethylsilyl acetate (TMSAc) monomer using RF capacitively coupled discharge in continuous and pulsed mode. Properties of prepared organosilicon coatings depend on the oxygen ratio in TMSAc/O2 gaseous mixture and pulse repetition frequency. The aging mechanism of TMSAc plasma polymers differs in dependency on deposition parameters. The application of pulsed mode significantly improved the stability of TMSAc coatings in contact with water. Abstract: In the present work, SiO x C y H z coatings were prepared in capacitively coupled RF glow discharge from gaseous mixture of trimethylsilyl acetate (TMSAc) monomer and oxygen. Properties of thin solid films prepared using continuous wave (CW) plasma and pulsed wave (PW) plasma were examined, including long–term stability in contact with air and water environments. The presented study proves that it is possible to prepare organosilicon coatings showing properties in a wide range from soft organic polymeric structures to materials similar to SiO2 with Martens hardness of 4 GPa. The content of carbon species in organosilicon structure and water contact angle (WCA) decreased with increasing oxygen ratio from 7.7 % to 75.0 %. The water contact angle of TMSAc-based coatings prepared in CW mode decreased from 95° to 76°. The application of pulsed mode using an oxygen ratio of 50 % and pulse repetition frequencies in the range of 0.33 Hz to 300 Hz led to materials with hydrophobic character (WCA in range of 86°–94°) with increased content of CH x and Si-CH 3 structures in comparison to CW mode. This study proves that the aging mechanism significantly depends on deposition parameters. The increase of oxygen ratio, as well as the increase of pulse repetition frequency, led to the higher resistance towards the atmospheric environment. On the other side, organosilicon coatings prepared in CW mode using high oxygen ratios (50–75 %) showed significant delamination after immersion in water. However, the use of PW plasma for the preparation of SiO x C y H z thin films significantly improved the stability of resulting materials under water environment.