FORMATION OF PLASMA POLYMER THIN-FILMS CONTAINING REACTIVE METAL CHELATE SITES

We report here the successful incorporation of chemically active Co2and Ni2+ centers into plasma polymer thin films. Metal center incorpor ation was accomplished by simultaneous plasma polymerization of sublim ed Co2+ or Ni2+ complexes with gaseous ''comonomers'' or Ar. The metal complexes include '-bis(salicylidene)-1,2-phenylenediaminecobalt(II) (CoS-alophen), N,N-bis(salicylidene)ethylenediaminecobalt(II) (CoSalen ), bis(3-fluorosalicylidene)ethylenediaminecobalt(II) (CoFluomine), me so-tetraphenylporphyrinatocobalt(II) (CoTPP), meso-tetraphenylporphine (TPP), and meso-tetraphenylporphyrinatonickel(II) (NiT-PP). Modificat ion to the metal complex structure was observed by IR and UV-vis spect roscopies. IR spectra of plasma polymer films containing the Schiff's base complexes, prepared using Ar as a carrier gas, contained a band a t 2190 cm-1, which can be attributed to nitrile group formation, and w ould necessarily result from destruction of the Co2+ inner coordinatio n sphere. This type of bond cleavage was eliminated by the use of poly merizable ''comonomers'' instead of Ar. IR spectra of CoFluomine films exposed to pyridine vapor indicate that pyridine is chemically bound within the films. Gravimetric analysis of the CoFluomine films reveale d that the pyridine is bound in a 1:1 Co:pyridine ratio, suggested tha t the metal center remains chemically active. IR spectra of plasma pol ymer films containing the porphyrin complexes contain evidence for mod ification to the phenyl and pyrrole rings, indicating that the complex es may be attached to the plasma polymer matrix at these sites. UV-vis spectra of plasma polymer films containing CoTPP contain a band at 61 0 nm which may be due to chlorin formation, which is consistent with p yrrole ring substitution. Plasma polymer film solubility in toluene wa s used to estimate the extent of cross-linking within the films. Solub ility was found to generally increase with increased concentration of complex in the films. This is discussed in terms of increased depositi on rate and decreased glow discharge pressure during synthesis of film s with higher metal chelate content.