SITE-SPECIFIC PHOTOCHEMICAL-REACTION OF PMMA BY CORE ELECTRON-EXCITATION

The photon energy dependence of photoion emission from solid films of poly(methyl methacrylate) was measured to investigate the primary steps in radiation induced decomposition following carbon and oxygen 1s electron excitations using monochromatic pulsed-synchrotron radiation. Various ions including the monomer ion were observed. Further it was clearly found that the decomposition depends on the nature of the electronic states created in the excitation process. Excitations of carbon 1s electrons to pi* and sigma* resonance states at 287.9 eV show remarkable enhancement of the ion emission for CH+ and CH2+. In the energy region of oxygen 1s electron excitation, the increase of COOCH3+ ion was not observed due to a fragmentation of the side chain by creating oxygen 1s hole.