Improvement in water and oil absorbency of textile substrate by atmospheric pressure cold plasma treatment

Cold plasma, an ionized mixture of gases with bulk temperature near the room temperature, can be safely used for surface modification of textile substrates. Plasma treatment can change surface hydrophilicity of the textile substrates by forming hydrophilic groups or can clean the surfaces by etching out top layers. With an aim to improve water absorbency of the textile substrates, nylon and polyester fabrics were treated continuously in an atmospheric-pressure-glow-discharge-plasma produced in presence of different gases. After plasma treatment, time taken in spreading a water droplet over a pre-defined area was found to decrease significantly. As expected, the chemical changes brought about by plasma, increased the surface energy of both nylon and polyester fabrics. However, the rate of oil absorption (a hydrophobic fluid) was also found to increase to a great extent. Spreading time for mustard oil droplet over a specified area was observed to decrease significantly from 152 s in an untreated fabric to 52 s in He plasma treated fabric for nylon, whereas, it decreased from 28.6 min in untreated fabric to 2.8 min in the treated fabric for PET samples. The effect of plasma treatment on the rate of oil absorbency was further confirmed for cotton fabrics, where the time for oil absorbency decreased from 59.5 s in the untreated sample to 30.4 s in the treated sample. The atomic force microscopy (AFM) analysis of the treated fabrics revealed the formation of nano-sized channels on their surfaces. The samples, after plasma treatment, showed only a marginal drop in their mechanical properties.