Hydrophobicity Improvement of PET Fabrics after SF ₆ Plasma Treatment

Abstract

We have used plasma assisted surface fluorination of polyethylene terephthalate (PET) fabrics to increase the water repellency of the fabrics. Treatment at different operating conditions for the radio-frequency inductively coupled in a SF ₆ atmosphere resulted in improved hydrophobicity. The water repellency of treated fabrics was characterized by water contact angle and absorption time measurement. The measured contact angle of optimum-treated fabrics was 140 degrees, and the absorption time was 210 min. The morphology changes in the surface of PET were obtained by scanning electron microscopy and atomic force microscopy. The rms surface roughness of PET was increased from 28 nm to 45 nm after plasma treatment. The changes in chemical composition were observed in X-ray photoelectron spectra (XPS) analysis. We found that the F/C atom ratios obtaining by XPS analysis on PET were correlated to the pressure, the RF power, and the treatment time. An increase in the F/C atom ratios seems to contribute to the absorption time.