Electron-Assisted Deposition-Polymerization in Vacuum of Polymethines with Terminal Allyl Group

Polymethines containing an allyl group have been synthesized. Their films are produced by physical vapor deposition (PVD) on glass, silicon (Si), gold (Au), polytetrafluoroethylene (PTFE), and nanostructured plastic substrates. Optical spectra recorded during the deposition showed no decomposition of molecules. The influence of dye structure and substrate on the morphology of the deposits is studied using atomic force microscopy (AFM). Depending on the dye structure and the substrate material, various nanostructures are grown. Dichroic nanowires (NWs) are formed by self-assembly on Au and Si substrates. On the Si surface, NWs grow between the edges of neighboring Au stripes. Several methods are used for the selective opening of the allyl group. Smooth films are produced with optical spectra similar to those deposited by PVD. The morphology of the films is dependent on the activation conditions. The thermal stability of the films exceeds the stability of those deposited via PVD. Allyl-terminated polymethines form self-positioned nanowires during evaporation and condensation in vacuum. The allyl group is activated in the gas phase without damaging the core chromophore. The relief of films deposited with activation is 10 times smaller than that of deposits produced by evaporation. The decomposition temperature of the films is higher than the dye evaporation temperature.dagger image