Depth / Conversion Characterization of Electron-beam Initiated Polymerization
Confocal Raman microscopy was used to determine polymer conversion as a function of depth into electron-beam cured coating samples. Samples were irradiated in atmospheres with varying levels of oxygen. As expected, conversion near the surface increased as the level of oxygen was decreased. Samples were also irradiated under well-inerted conditions while varying the accelerating potential (voltage) of the electron beam. The results show low conversion near the sample bottom at the lower voltages. This lower conversion is consistent with inadequate energy penetration predicted by Monte Carlo simulations.
IONIZING RADIATION AND POLYMERS
Literature concerning the influence of ionizing radiation on macromolecular substances is reviewed. From this point of view, some established relations determining the course of polymerization reactions initiated by ionizing radiation, the radiochemical preparation of grafted copolymers, and the effect of radiation on solid polymers resulting either in degradation or in the formation of a cross-linked structure are treated. 64 references. (auth)
Submicron polymer structures with X-ray lithography and hot embossing
This article describes the process chain for replication of submicron structures with varying aspect ratios (AR) up to 6 in polymethylmethacrylate (PMMA) by hot embossing to show the capability of the entire LIGA process to fabricate structures with these dimensions. Therefore a 4.7 μm thick layer of MicroChem 950k PMMA A11 resist was spin-coated on a 2.3 μm Ti/TiOx membrane. It was patterned with X-ray lithography at the electron storage ring ANKA (2.5 GeV and λc ≈ 0.4 nm) at a dose of 4 kJ/cm3 using a Si3N4 membrane mask with 2 μm thick gold-absorbers. The samples were developed in GG/BDG and resulted in AR of 6–14. Subsequent nickel plating at 52°C resulted in a 200 μm thick nickel tool of 100 mm diameter, which was used to replicate slit-nozzles and columns in PMMA. Closely packed submicron cavities with AR 6 in the nickel shim were filled to 60% during hot embossing.