Modification of Polydimethylsiloxane Coatings by H2 RF Plasma, Xe2 Excimer VUV Radiation, and Low-Energy Electron Beams

The crosslinking of thin liquid PDMS layers by three different technically relevant processes, H2 radio‐frequency plasma treatment, Xe2* excimer VUV irradiation, and low‐energy electron beam processing is investigated. The modifications to the layers due to the processing are monitored by means of RAIRS. Plasma processing of liquid PDMS leads to a direct conversion to a SiOx‐like material of the topmost layers, whereas a gradual transition from PDMS to the same product is observed upon VUV irradiation. Electron exposure does not induce oxidation. The initiating steps of the conversion induced by the interaction with VUV photons, low‐energy electrons, or their combined effect with ions and H atoms in the plasma are discussed. The latter creates a high density of damage sites. Thin layers of polydimethylsiloxane are processed by H2 radio‐frequency plasma, Xe2* excimer VUV light, and a low‐energy electron beam. Reflection/absorption infrared spectroscopy reveals characteristic differences in the chemical modifications induced by these processes. They are explained by the nature of the initial interaction with the involved energetic quanta or particles.