| Abstract
| - Glow-discharge-induced sublimation (GDS) is used to deposit thin films of polyimideprecursor monomers, i.e., 2,4,6-trimethyl m-phenylenediamine (TMPD), 4,4‘-hexafluoroisopropylidene dianiline (6FDAm), 3,3‘-diaminodiphenyl sulfone (DDS), 4,4‘-hexafluoroisopropylidene diphthalic anhydride (6FDA), and 3,3‘,4,4‘-biphenyltetracarboxylic acid dianhydride(BPDA). Monomer films are also deposited by vacuum evaporation (VE) for the sake ofcomparison. In situ mass spectrometry points out both the sublimation of integer monomermolecules and the presence of molecular fragments in the glow discharge. AFM images ofthe film surfaces indicate that GDS allows obtention of smoother surfaces with respect toVE for most of the monomers. FT-IR analysis and UV−Vis fluorescence spectroscopy showthat the deposition of integer monomer molecules onto the substrate and the partialincorporation of molecular fragments take place. In particular, the fluorescence features ofGDS samples are different from those of VE samples and depend on the incorporatedmolecular fragments whose optical properties are similar to those of amorphous hydrogenatedcarbon structures.
- Five polyimide precursor monomers are deposited by glow-discharge-induced sublimation (GDS) to study the ion bombardment effects and the condensation of monomer molecules. The molecular structure of the monomers determines the fluorescence properties of the deposited coatings, which is related to the incorporation and aggregation of molecular fragments in the deposited films.
|
