Functionalization of Suspension Sprayed TiO2 Coatings by Direct Laser Interference Patterning

Suspension spraying has been investigated for the manufacture of coatings for high ranges of applications, such as, photocatalysis, thermal barrier coatings, mechanical, biomaterials or superhydrophobicity. Even though these coatings are already very promising, a modification of their surface properties can further improve their functionality and lifetime in order to meet the growing requirements of the demands. Direct laser interference patterning (DLIP) is a versatile laser technology which allows fabricating microstructures with high flexibility and therefore designing surface properties on a large diversity of materials, including metals, polymers, ceramics and coatings. In this contribution DLIP technology was applied to modify the surface topography of suspension sprayed TiO₂ coatings. In particular, a nanosecond-pulsed laser has been employed to produce line-like micro-structures and the effect of pulses overlapping on the coating properties was investigated. The top-surfaces and cross-sections of the coatings were characterized by scanning electron microscopy. Raman spectroscopy measurements were performed in order to determine the phase composition on the coating surfaces. The influence of the laser treatment on the photocatalytic activity and wettability behavior has been investigated. The results showed that the DLIP technology is suitable for designing and tailoring of the surface properties of the suspension sprayed coatings.