Nano roughening of PET and PTT fabrics via continuous UV/O3 irradiation

Continuous surface treatment of PET and PTT fabrics was carried out to introduce nanoscale surface roughness using an electrodeless UV bulb for different periods of time. Reflectance of the irradiated fabrics decreased in the low wavelength regions of visible light, especially at 400 nm. The surface roughness of the irradiated fabrics was investigated to verify the scattering and destructive interference of visible light using SEM and AFM analyses. AFM images indicated that the treatment developed the nano-sized roughness on the polyester surfaces. The surface roughness increased by two-fold from 58 nm to 122 nm in terms of peak–valley roughness, which can interfere destructively the incident light of as high as 488 nm wavelength in the visible spectrum. The dyeability of the surface modified polyester fabrics to disperse dyes was similar to that of untreated fabrics. However, irradiation both after and before dyeing with black disperse dyes significantly decreased lightness of the dyed fabrics up to 8% with increasing treatment due to the enhanced surface roughness. Surprisingly color fastness of the dyed polyester fabrics was excellent because of surface-limited treatment of the polyester fabrics.