David Waugh

TL;DR: In this article, a CO2 laser marker was used to produce trench and hatch topographical patterns with peak heights of around 1 μm on the surface of nylon 6,6 and the patterns generated have been analyzed using white light interferometry, optical microscopy and X-ray photoelectron spectroscopy to determine the surface oxygen content.

TL;DR: The surface modification of PMMA with a CO2 laser in order to vary the wettability characteristics was investigated by generating a number of patterns of various topography on the surface using the CO2-laser.

TL;DR: In this paper, a comparison of three different industrial solid-state laser sources providing four different wavelength/pulse duration combinations were used for texturing Ti-11.5Mo-6Zr-4.5Sn β-Ti alloy with different laser wavelengths and pulse durations.

TL;DR: The results indicated that the laser-induced surface features, such as surface roughening, presence of anisotropic dendritic pattern and complete surface Ni oxidation were beneficial to improve the biocompatibility of NiTi as evidenced by the highest cell attachment and viability found in the MZ.

Abstract: Enhancement of the surface properties of a material by means of laser radiation has been amply demonstrated previously. In this work a comparative study for the surface modification of nylon 6,6 has been conducted in order to vary the wettability characteristics using CO2 and excimer lasers. This was done by producing 50 μm spaced (with depths between 1 and 10 μm) trench-like patterns using various laser parameters such as varying the laser power for the CO2 laser and number of pulses for the excimer laser. Topographical changes were analysed using optical microscopy and white light interferometry which indicated that both laser systems can be implemented for modifying the topography of nylon 6,6. Variations in the surface chemistry were evaluated using energy-dispersive X-ray spectroscopy and x-ray photoelectron spectroscopy analysis and showed that the O2 increased by up to 1.5% At. and decreased by up to 1.6% At. for the CO2 and F2 laser patterned samples, respectively. Modification of the wettability characteristics was quantified by measuring the advancing contact angle, which was found to increase in all instances for both laser systems. Emery paper roughened samples were also analysed in the same manner to determine that the topographical pattern played a major role in the wettability characteristics of nylon 6,6. From this, it is proposed that the increase in contact angle for the laser processed samples is due to a mixed intermediate state wetting regime owed to the periodic surface roughness brought about by the laser induced trench-like topographical patterns.