Effect of 13.56 MHz radio-frequency plasma treatment time on the surface modification of high density polyethylene sheets

Abstract

Plasma surface modification of polymers are done to improve surface properties. This work uses oxygen (O2) radio frequency (RF) plasma to treat high density polyethylene (HDPE) for surface modification. The contact angles of water and diiodomethane on the untreated HDPE was 78° and 47°, respectively. The wettability of the surface increased after treatment with O2 RF plasma at 40W RF power. The surface energy increases with treatment time with a maximum surface energy of 60.22 mN/m exhibited by the sample treated for 10 min. The surface roughness also increased with increasing treatment time reaching up to 2.71 nm RMS roughness. Formation of a broad C=O bond in the 1700-1500cm-1 region was assumed to be the cause of the increase in wettability after plasma treatment. HDPE with controllable wettability, surface energy, surface roughness and functionality is useful in composite applications usually found in the construction industry.