XeCl laser ablation of polyimide: Influence of ambient atmosphere on particulate and gaseous products

The gaseous and particulate products of the XeCl (308 nm) laser ablation of polyimide (Kapton H) are quantitatively determined and compared with the mass loss of the polymer in atmospheres of He, N2, air, or O2. In air and in pure O2, the observed mass balance is about 90%, but is lower for inert atmospheres. With increasing oxygen content in the atmosphere, the yield of CO2 increases at the expense of particulates and acetylene. The influence of laser fluence and nature of the ambient atmosphere on the product distribution is interpreted in terms of ejection of small reactive species which are involved in the competitive reactions of particulate formation and oxidation to CO2.