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▶ In this paper, we have applied the method of direct laser interference patterning to produce periodic patterns on hydroxyapatite, using UV ration (266 and 355nm). Line- and cross-like patterns with periodical distances of 10 and 20μm were fabricated with different energy densities as well as pulse numbers. ▶ The results here presented show an alternative route for the direct fabrication of micro patterns on ceramics. Compared to other techniques such Aerosol-Jet-printing or microcontact printing, only one step is necessary to fabricate the micropatterns, and high fabrication speeds, even on non-planar substrates, can be achieved.
Direct laser interference patterning (DLIP) was used to produce periodic patterns on hydroxyapatite. A Nd:YAG laser operating at 266 and 355nm wavelengths and a pulse duration of 10ns was used in these experiments. Line- and cross-like patterns with periodical distances of 10 and 20μm were fabricated with energy densities between 0.6 and 2.4J/cm2, and pulse numbers from 1 to 100. In the low/middle laser intensity range it was observed that the structure depth increased with the pulse number. However, for higher energies the patterns smudge due to thermal effects. For single pulse laser experiments, increasing of the laser fluence did not produce deeper structures. In addition, the best results were obtained when using low-medium laser intensities (∼0.6–1.2J/cm2) and moderate number of laser pulses (20–50), depending on laser wavelength. In addition, at a 355nm wavelength only patterns with 20μm periods presented a good quality structure. In contrast, 266nm wavelengths permitted to improve resolution up to periods of 10μm due to a higher photochemical contribution to the ablation process. X-ray Photoelectron Spectroscopy (XPS) analysis showed that there are no significant changes in the chemical composition of laser-treated hydroxyapatite.