Plasma polymerization of C4Cl6 and C2H2Cl4 at atmospheric pressure

In the present study, the feasibility of synthesizing chlorinated films by a dielectric barrier discharge at atmospheric pressure is assessed. Two different liquid monomers (hexachlorobuta-1,3-diene C4Cl6 and 1,1,1,2-tetrachloroethane C2H2Cl4) are tested and results show that organic coatings rich in chlorine can be deposited. The correlation and complementarity of water contact angle, X-ray photoelectron spectroscopy, secondary ion mass spectrometry and ellipsometry techniques have provided information to compare the properties of the perchlorinated layers built up from monomers with different Cl/C ratios and hydrogen concentrations. The bond dissociation energies of C–Cl2, C–Cl and C–C/CC/C–H are used to provide an explanation for the differences in films structure recorded by X-ray photoelectron spectroscopy and secondary ion mass spectrometry. Finally, dynamic-secondary ion mass spectrometry complemented by ellipsometry is used to calculate a deposition rate ranging from 40 to 70 nm/min depending on the plasma conditions. These measurements also show a good homogeneity of the film throughout its thickness.