Martin Kral

Effect of hydrogen on amino group introduction onto the polyethylene surface by surface-wave plasma chemical modification

This work reports the effect of hydrogen concentration on the amino group introduction by the plasma treatment of the polyethylene surface. The amino group selectivity on the polyethylene sheet treated by the surface-wave plasma in various N2/H2 gas mixtures was examined by chemical derivatization combined with x-ray photoelectron spectroscopy (XPS). Amino derivatization along with XPS was employed in order to evaluate the amount of the introduced amino group. The highest concentration of the amino group, about 2.0 in amino-N/100 C-atoms, was obtained in the case of ammonia plasma treatment as well as the highest amino selectivity of about 100% in the amino-N/N ratio.

Surface Amination of Biopolymer Using Surface-Wave Excited Ammonia Plasma

Surface-wave plasma has been used to modify polymer surfaces. The density and selectivity of the functionalizations are very important for biomaterial applications. Low-temperature plasma treatment has been successfully applied to many types of polymers to generate functional surfaces. In this study, we focus on the surface modification of amino groups on chitosan surfaces by ammonia plasma treatment. Chitosan is a nontoxic, biocompatible and biodegradable polymer, which promotes the scarless healing of skin through embolization. The experimental results of X-ray photoelectron spectroscopy measurements showed that the ammonia plasma exposure to the chitosan surface increased the nitrogen incorporation on the surface from 4.67 to 9.92%. The selectivity of amino group functionalizations (–NH2/N) increased from 53.7 to 78.4% after the plasma irradiation.

Effect of Ar and N2 Plasma Pretreatment with Biased Sample Holder on Amino Group Introduction Onto Polyethylene Sheet Treated by Ammonia Plasma

The effect of the plasma pretreatment using a biased sample holder on amino group introduction onto a polyethylene (PE) surface is reported. Ar or N2 plasma was used for the pretreatment and was followed by ammonia plasma treatment for 30 s. X-ray photoelectron spectroscopy (XPS) and chemical derivatization were used in order to estimate the concentration of the introduced amino group. In both cases of plasma pretreatment, the reactivity of the surface increased, and the overall nitrogen concentration on the PE surface increased. In the case of Ar pretreatment, we observed no significant change in amino group introduction compared with that without pretreatment, whereas in the case of N2 pretreatment, the concentration of amino groups decreased by about 40%.

Low-Temperature Nitrogen Introduction onto Polyurethane Surface Using Surface-Wave Excited N2/H2 Plasma

In this article, we report the results of the low-temperature chemical modification of a polyurethane (PU) surface using surface-wave excited N2/H2 plasma. Optical emission spectroscopy (OES) and double-probe measurement were performed to obtain optimum plasma properties. X-ray photoelectron spectroscopy (XPS) was employed to characterize the changes on the PU surface and to estimate the amount of introduced nitrogen-containing groups. The result shows that the largest amount of increase was obtained in the case of 90% N2/(N2 + H2) plasma where the N/C ratio on the PU surface increased from 0.0128 before plasma treatment to 0.131 after plasma treatment.