Figure 7. Evolution of WCA of the samples produced in the ambient air and aged up to 30 days in air. HP is the polarization direction of laser field perpendicular to direction of scanning, VP is the direction of laser field parallel to direction of scanning and CP is circularly polarized laser beam.
Strongly irradiated surface at initial periods of air ageing demonstrates hydrophilic properties, but for later times (>2 days) the pace of changing is increasing and outperforms initial WCA. Final result of ageing in Fig. 7 demonstrates no noticeable dependence on the morphology generated by applying different laser polarizations.
Figure 8 shows relation of the presence of the C (black bars) and O (cyan bars) for mesh samples after 30 days of ageing. For all samples we see the increase of the relative amount of carbon C on the textured surface. This amount lower than in case of samples stored inside Chamber #2 (Fig. 5), that can explain lower WCA in the case of air aged samples.