Table 3 shows the colour fastness properties of untreated and plasma-nano chitosan treated samples dyed with acid dyes. Samples dyed after plasma-nano chitosan treatment showed better wash fastness, which may be due to ionic and physical attraction between newly formed functional groups on the plasma-nano chitosan treated of cotton/nylon fabrics and acid dyes. There is no considerable difference between the colour fastnesses to light of the samples, but the crocking fastness is still lower in the case of the low concentration of chitosan treated fabrics. As mentioned before, plasma enhances chitosan absorbance, but, because of the nature of plasma treatment, the chemical modification made by plasmaprocesses is restricted to the surface of the material. Therefore, some of the dye molecules are adsorbed to the near-surface layers of the plasma-nano chitosan treated fibers and can be removed easily when subjected to a crocking test. However at high chitosan concentration, non-electrostatic interaction between chitosan nanoparticles and individual cellulose fiber bring in more chitosan throughout fibers which makes adequate ionic bonding with dye molecules. The fastness values of all such dyed samples are quite improved whereas untreated sample shows poor washing and crocking fastness properties.