Emission spectroscopy was applied to observe decomposed species of N-isopropylacrylamide (NIPAAm) exposed to He plasma, which was generated by AC discharge at the pressure of 400 Pa. As the NIPAAm monomer was exposed to He plasma, light emitted from the NIPAArn and plasma was monitored. In the diagnosis measurement, several emission peaks assigned to the H, and Hp atomic lines, CH3O, CN(B-2 Sigma-X-2 Pi),CH(A(2)Delta-X-2 Pi), and C3H5, CN, CHO, CH2O, and C4H2+ transitions were observed and measured at various discharge times. The present results show the presence Of C4H2 and C4H2+*, which are not manifested in great concentration in the Simulation of RF acetylene discharge. The time dependence of the emission intensities was also investigated. When the discharge time of He plasma was increased, the emission intensities of the observed transitions also increased and then gradually decreased. (c) 2006 Wiley Periodicals, Inc.