Polymer Surface Treatment with SO₂ -Containing Plasmas

Abstract

Polyethylene, poly(propylene), and polyester were treated with sulfur dioxide plasma and with plasmas using a mixture of SO2 with oxygen or with hydrogen. Depending on the process gas and the treatment conditions the functional groups formed by the plasma treatment can be sulfides or groups with highly oxidized sulfur such as sulfonic acid groups and sulfates. XPS and infrared reflection absorption spectroscopy (IRRAS) were used to identify the surface functional groups. The acidic groups (sulfonic acid, hydrogen sulfates) were quantified by fluorescence labeling with dansyl cadaverine. Values of up to 820 pmol · cm−2 were found. The acidic functional groups were also used as starting points for further functionalization of the surfaces. In the reaction with diamino ethane, primary amines were produced on the surface.

Sulfur dioxide Plasma Treatment of the Clay (Laponite) Particles

“…This can be explained by the fact that under such gas flow conditions (60 sccm) in the plasma phase the higher concentration of the active species is present. So, increased sulfur content values with the increase of the plasma RF power can be assigned to the enhanced conversion of SO 2 gas to acid-functional moieties [20]. This explanation is confirmed by the increase of the slope of obtained kinetic curves with the growth of the RF power (Fig.…”

“…The nature of the S-containing groups was investigated using high resolution scans of the S 2p peaks (Fig. 8) and the found binding energy values were compared with the literature [9,19,20]. The fitted spectra match experimental data very well.…”

“…The fitted spectra match experimental data very well. The observed binding energy suggests that a significant fraction is sulfur with four surrounding oxygen atoms, and the signal can be assigned to sulphate moieties [9,20]. Besides, there is no indication of S 2-species (expected at a binding energy near 164 eV [19]) (Fig.…”

“…Also, it has been shown that the hydrophilic surface created by the SO 2 plasma treatment is more trombogenic than the untreated control [10]. Hollander et al have shown that SO 2 plasma treatment allows obtaining a surface with a high concentration of S-functional groups [20].…”

A Detailed Description of the Chemistry of Thiol Supporting Plasma Polymer Films

“…Indeed, considering the complex sulfurbased multifunctional surface generated by the plasma polymerization process, the chemical shifts associated to the different functionalities are too low compared to the energy resolution of the XPS for allowing an accurate spectral curve fitting of both the C1s and S2p photoelectrons peaks. [20,21] Therefore, in order to probe the -SH density in the coatings, we have recently established a chemical derivatization method using N-ethylmaleimide as a labeling molecule. [22] This derivatization method in combination with XPS is used in this work to specifically probe the evolution of the -SH density for several sets of experimental parameters.…”