Uniform surface modification of polyethylene terephthalate (PET) by atmospheric pressure plasma jet with a horn-like nozzle

Abstract

This work reports on surface modification of polyethylene terephthalate (PET) polymer by an atmospheric pressure plasma jet (APPJ) operated with argon. A distinguishable feature of this device is that it terminates with a conical horn-like nozzle. Three different nozzles diameters were employed with the purpose to obtain uniform surface modification over large area. Treatments in small 3D objects that fit inside the conical horn were also conducted. In this study, water contact angle (WCA) measurements and X-ray photoelectron spectroscopy (XPS) were performed to assess the samples wettability and the surface elemental composition, as well as, their radial distribution. Plasma-induced changes on the polymer surface morphology were evaluated by Atomic Force Microscopy (AFM). Electrical characterization of the plasma and investigation of the effect of the gas flow rate on the discharge power were carried out. After the plasma treatment PET surface became more hydrophilic over the entire area covered by the nozzle. This effect is caused by the incorporation of oxygen containing polar groups on the surface. It was also observed that depending on process parameters, the plasma treatment can extend even outside the area of the conical horn. The degree of surface modification depends on plasma dose while the treatment uniformity is determined mostly by the distance to the sample. Overall, a quite uniform surface modification was obtained over the entire area covered by the jet nozzle. Thus, the results suggest that by simply changing the jet geometry and choosing the right treatment parameters one can achieve a uniform treatment over an area whose size is determined by the horn diameter.

Study of Modified Area of Polymer Samples Exposed to a He Atmospheric Pressure Plasma Jet Using Different Treatment Conditions

“…However, it has been reported that the simultaneous operation of many plasma jets can be challenging due to the strong electric repulsion between the neighboring plasma plumes resulting in plasma plume misalignment and, consequently, a non-uniform treatment [21]. Another alternative was reported by Mui et al [22], where a plasma jet terminating with a horn-shaped nozzle was used for the treatment of PET samples. The 60-mm-diameter conical nozzle allowed a homogeneous treatment over the entire PET sample that lies inside the horn.…”

Cold Atmospheric Pressure Plasma Jet for the Improvement of Wettability of Polypropylene

“…At first, the contact angles on the control sample for water and glycerol were 94.5 °and 84 °, but after plasma jet treatment, the contact angles were reduced to 57 °and 65 °, respectively, and became constant after a treatment time of 30 seconds. The reduction in contact angle might be due to the increase in roughness on the surface of PP [14,19,29,30]. 5 International Journal of Polymer Science Figure 6 shows the variation of surface energy and its polar and dispersive components of PP samples with a treatment time of 120 seconds.…”

Generation and Characterization of an Atmospheric-Pressure Plasma Jet (APPJ) and Its Application in the Surface Modification of Polyethylene Terephthalate

“…Initially, the contact angle of the untreated PET for water and glycerol was 82°and 88°, but after plasma treatment, the contact angle was effectively reduced to 26°and 30°, respectively, and became almost constant after the treatment time 50 seconds as shown in Figure 5. The reduction in the contact angle might be due to the change in the surface roughness as seen from SEM and AFM micrographs [23].…”