Synthesis, Structure, and Properties of Alkyl-Substituted PPXs by Chemical Vapor Deposition for Stent Coatings

High-molecular-weight un-cross-linked poly(<i>p-</i>xylylene) (PPX) derivatives (<b>3</b>) with one lateral linear alkyl substituent (methyl–octyl) on each phenylene moiety were prepared by pyrolysis of corresponding paracyclophanes followed by chemical vapor deposition (CVD). Most of these PPX derivatives showed good solubility in organic solvents which allowed purification by reprecipitation, structural analysis by solution NMR techniques, and molecular weight analysis by gel permeation chromatography. High thermal stability of <b>3</b> was found by thermogravimetric analysis. The glass transition temperatures decreased systematically with increasing alkyl chain length from 53 to −23 °C. Increased elongation to break up to 380% was analyzed by stress–strain experiments for as-deposited films indicating excellent coating properties, which were proven by initial coating tests on stents