Tailoring surface morphology of cotton fibers using mild tetrafluoromethane plasma treatment

Abstract

Surface morphology of woven cotton fabrics was modified by treatment with mild plasma created in tetrafluoromethane (CF4) at the pressure of 60 Pa. Samples of dimensions 20 cm × 20 cm were mounted into a 27-cm-wide cylindrical plasma reactor powered with a radio frequency generator of frequency 27.12 MHz and output power of about 500 W. The volume of the reactor was 17 l and the corresponding power density was solely 30 W/l. The plasma density was estimated with a double electrical probe and was about 2 × 109 cm−3. The type of radicals created in plasma was determined using optical emission spectroscopy (OES). No CFx and a negligible amount of F radicals were observed by OES, and surprisingly the predominant spectral features were CO bands. The evolution of surface morphology vs. plasma treatment time was monitored by scanning electron microscopy. Originally smooth fibers became extremely rough after prolonged treatment. The results were explained by etching of fibers with gases released from the samples upon plasma treatment.