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Study on surface structure of plasma‐treated polydimethylsiloxane (PDMS) elastomer by slow positron beam
Author(s) -
Wang Zheng,
Luo Yi,
Zheng Feng,
Zhang Ni,
Yin Chongshan,
Li Jingjing,
He Chunqing,
Peng Xiangyang,
Huang Zhen,
Fang Pengfei
Publication year - 2018
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.6484
Subject(s) - polydimethylsiloxane , siloxane , scanning electron microscope , x ray photoelectron spectroscopy , elastomer , layer (electronics) , materials science , analytical chemistry (journal) , plasma , surface layer , positron , composite material , chemistry , chemical engineering , electron , polymer , chromatography , physics , quantum mechanics , engineering
In this paper, the variations in surface structure of polydimethylsiloxane elastomers before and after argon plasma treatments have been investigated by X‐ray photoelectron spectroscopy, slow positron beam, and scanning electron microscope. An inorganic silica‐like layer was probed by X‐ray photoelectron spectroscopy after 3 minutes or longer time of treatments, and the sample surface turned into totally hydrophilic. Short time (1 and 2 min) plasma exposure mainly removed preexisting low molecular weighted (LMW) siloxanes on sample surface. By using slow positron beam, the thicknesses of silica‐like layer for 3‐, 5‐, and 10‐minute–treated samples were estimated to be around 30, 66, and 91 nm, respectively. Beneath the silica‐like layer, a loose polymeric structure was also detected, which was ascribed to the accumulation of LMW siloxanes. Scanning electron microscope images showed that the silica‐like layer cracked after 10 minutes of plasma treatment, which provided direct diffusion pathways for LMW siloxanes. Hence, 10‐minute–treated sample showed rather low organic composition near surface. Slow positron beam provides valuable depth profile information for evaluating the surface aging condition of polydimethylsiloxane composite.