VUV-induced photopolymerization of acrylates

摘要

Acrylates and methacrylates are photopolymerized without photoinitiator by exposure to 172 nm radiation. The kinetics of the polymerization is studied using real-time Fourier-transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy. It is shown that layers with a thickness of ≈500 nm can be polymerized very rapidly. The effect of structure, viscosity, functionality, and absorption of the acrylates as well as the influence of temperature and oxygen concentration on the reactivity are studied. A strong conversion gradient is observed in layers up to ≈2 μm thickness, which reflects the intensity gradient within the layer. However, the penetration of the polymerization into the layer exceeds the initial penetration depth of the VUV radiation, which indicates strong bleaching of the acrylates during irradiation.