Comparative study on the decomposition process of N-isopropylacrylamide in He, N2 and air plasmas

Emission spectroscopy was employed to observe decomposed species of N-isopropylacrylamide (NIPAAm) exposed to He, N2 and air plasmas, which were generated by an AC discharge at 3.0 Torr pressure. For the He plasma, several strong emissions were observed and assigned to the Hα and Hβ atomic lines, CH3O, CN(B 2Σ-X 2Π), CH(A 2Δ-X 2Π), N2+(B2Σu+-X2Σg+), N2(C 3Πu-B 3Πg) and C3H5, CN, CHO, CH2O and C4H2+ transitions. These results suggest that plasma etching decomposed the NIPAAm monomer sample, and the resulting species emitted light near the surface. For the NIPAAm exposed to N2 plasma, the emission spectrum shows the presence of the following species: N2+ , N2, NH, NH+, CO and OH, while when the NIPAAm was exposed to the air plasma, the species observed were N2+, N2, NH, NH+, CO, OH and O. Most of the bands and lines observed in helium plasma were not present in air and nitrogen plasmas. This implies that these species undergo significant chemical conversion in the plasma. The time dependence of the strong emission intensities of the observed species was also investigated. As N2 and air plasmas were exposed to the NIPAAm monomer, the surface was etched more rapidly than the He plasma