Erzeugung substituierter Poly(p-xylylen)e durch Gasphasenabscheidung

This thesis describes the synthesis of different mono- and disubstituted [2.2]paracyclophanes and their use as precursor molecules in chemical vapor deposition (CVD), the so called Gorham process, to polymerize thin Poly(p-xylylene) (PPX) films on various substrates. The aim was to use modified precursors to directly incorporate functional groups into the polymer by CVD. Ideally the bulk and surface properties of PPX (unfunctionalized polymer) are completely changed. This avoids laborious post-treatments of the polymer films which often lead to insufficient modification. Promising results were achieved by siloxane, alkyl and alkyl-fluorine modified precursors which led to hydrophobic, transparent and highly expandable polymer films with low glass transition temperatures and significantly different properties than the basis polymer Parylene N. Initial stent coating tests with Poly(n-propyl-p-xylylene) led to conformal coatings and no crack formation after stent expansion. The good solubility especially for PPX with long side chains allowed the analysis of the polymers in solution. NMR spectroscopic data hypothesize a head-to-tail, a head-to-head and a tail-to-tail connection in the polymer comparable to polymers synthesized with the Gilch-route. For the first time GPC measurements of CVD PPX based on [2.2]paracyclophanes allow an estimation of average molecular weights and polydispersities. The high average molecular weights found correspond to previous calculations of molecular weights by ESR measurements.