Acetylene plasma polymer treated by atmospheric dielectric barrier discharge

• Acetylene plasma polymers (pp-acetylene) were deposited by PECVD.
• Atmospheric dielectric barrier discharge was used to treat pp-acetylene.
• Molecular structures of the thin films were investigated by FTIR.
• The surface roughness of the samples was performed by AFM.
• It was used contact-angle to investigate the wettability of the samples.

Plasma polymer films are very attractive for industrial applications in several sectors such as in the electronic, mechanic, biomedic, coating and others, due to its good adhesion, being insoluble in mild acids and bases and having a high crosslinking structure. This work reports the physical, structural, and surface properties of the polymer obtained from an acetylene plasma polymerization technique and treated by dielectric barrier discharge (DBD). The film was deposited in a reactor supplied by a radio-frequency power source at low pressure. After deposition, the nanofilms were treated in a DBD plasma reactor operating in air. The treatment times varied from 1 to 5 min. The analysis of molecular structure of the samples was investigated by FTIR spectroscopy, showing absorption bands in 3480, 2930, 1720, 1450 and 1380 cm−1. The water contact-angle was investigated by goniometric technique and presented values from 5 to 65°. The aging effect of these films was also studied. The alteration in the films surface morphology was assessed by an atomic force microscopy (AFM) which indicated that the roughness increased from 60 nm to 160 nm as a result of the DBD treatment. The refractive index of the samples presented values near 1.7, measured by UV–Visible spectroscopy.