Comparative Study of Ultraviolet and Infrared Femtosecond Laser Irradiation on Textile Polymers PET and PA66

Femtosecond lasers emit short pulses whose temporal width is in the range of less than a pico-second to a few femtoseconds (fs), thereby enabling extremely high peak-power machining with minimum thermal damages. Herein, we employed femtosecond laser pulses as a versatile tool for surface processing of 2 polymers commonly used in textile industry, Polyethylene terephthalate (PET), and Polyamide66 (PA66). This work focuses on a comparison of ultraviolet (UV, 257 nm) and infrared (IR, 800 nm) femtosecond laser irradiation at the surface of the polymers PET and PA66. The polymers are modified topographically and chemically, by direct laser irradiation, through different ablation routines, with direct bond breaking for UV fs laser irradiation, and multi-photon absorption for IR fs laser irradiations. The interaction strongly depends on the laser beam operation conditions, such as laser fluence, number of pulses, wavelength etc, as illustrated by post mortem analysis based on optic microscopy, Scanning Electron Microscopy and Raman spectroscopy. This work defines the change in the characteristics of the polymers as a function of the laser wavelengths. UV fs laser processing appears to be more advantageous, offering a large process window and a high precision in ablation.