Improvement of Hydrophilicity of Polypropylene Film by Dielectric Barrier Discharge Generated in Air at Atmospheric Pressure
Rajesh Prakash Guragain, Hom Bahadur Baniya, Santosh Dhungana, Ganesh Kuwar Chhetri, Saurav Gautam, Bishnu Prasad Pandey, Ujjwal Man Joshi, Deepak Prasad Subedi.
The industrial use of polypropylene (PP) films is constrained due to their unattractive properties like poor wettability, printability and adhesion. In the present study, a dielectric barrier discharge (DBD) is employed to enhance the surface properties of PP. A sinusoidal power supply with discharge voltage of 13 kV (r.m.s), and frequency of 50 Hz was used for the generation of the discharge. The change in wettability of treated PP film surface was measured in terms of water contact angle (WCA). In addition, changes in morphological composition of control and treated films were inspected by scanning electron microscopy (SEM) and atomic force microscopy (AFM). SEM and AFM observations on the polymer samples showed increment in roughness of the surface due to DBD operation. After the plasma treatment, WCA was found to change from 90.8° ± 1.8° to 73.6° ± 0.9°, which indicated that the surface had changed to a hydrophilic state caused by an increase in the surface roughness and incorporation of polar functional groups into PP surface.
Key words: Dielectric barrier discharge (DBD), polypropylene (PP), optical emission spectra (OES), water contact angle (WCA), surface free energy (SFE), surface morphology, surface modification