SUB-MICROMETER PERIODIC SURFACE STRUCTURE PRODUCED ON PET FIBRES WITH A LOW-FLUENCE ULTRAVIOLET EXCIMER LASER

The effects of low-fluence laser on polyethylene terephthalate (PET) fibres are reported in this work. Laser Induced Periodic Surface Structures (LIPSSs) are formed on the fibres by using a 248 nm uv excimer laser with a fluence below the ablation threshold of the material so that no removals are involved in the treatment. The optimum conditions for forming a successful periodic ripple structure on PET fibres are 6 mJcm^-2 of laser fluence and 2000 shots of laser pulses. Other than the fluence and pulse number of the laser, its degree of polarization, the direction of polarization and the curvature of the fibre surface also play important roles in forming the structures. All of these effects are reported in this work, which highlights the distinctive features of the surface profile and its production in comparison with those of LIPSSs on PET fibres due to high-fluence lasers, and of LIPSSs on PET films due to low-fluence lasers.