The role of molecular and radical mobility in the creation of CO2 molecules and OH groups in PADC irradiated with C and O ions

Abstract We report the loss of carbonate ester and the creation of embedded CO 2 molecules and OH groups in poly (allyl diglycol carbonate) (PADC) irradiated with C (11 MeV/u) and O ion (7.5 MeV/u) beams under vacuum at low temperatures (11, 100 and 200 K) and at room temperature (RT) using in-situ FT-IR spectrometry. For comparison with these experiments, the behavior under O ions (6 MeV/u) irradiations in ambient air is examined by off-line FT-IR spectrometry. The radiation chemical yield for loss of carbonate ester (G-carbonate) in PADC irradiated with O ions at 11 K is lower than that obtained at RT. Furthermore, the G value of embedded CO 2 molecules (G-CO 2 ) under O ion decreases with decreasing temperature. As CO 2 molecules have been said to be formed from the fragmentation of carbonate groups, G-CO 2 is compared to G-carbonate. For given temperatures, G-CO 2 is significantly lower than G-carbonate. These findings imply that the molecular and radical mobility is crucial for CO 2 formation after damage to carbonate groups. As for OH groups, their formation under vacuum is suppressed at low temperatures and a tenuous formation is observed at RT. Oxygen and potentially water molecules, which are present in ambient air, play important roles in the formation of OH groups as new end-points.