Multiscale ultrafast laser texturing of marble for reduced surface wetting

Application of Femtosecond Laser Processing Method in the Sustainable Conservation of Stone Cultural Relics: An Example of Green Schist in Wudang Mountain, China

“…The muscovite composition forms a melt based on the single scan of the femtosecond laser and sputters some of the melt by the impact of the femtosecond laser ablation. Some regions form a micro-nano structure similar to the surface of the lotus leaf by depositing the melt [31]. However, the content of muscovite is only about 15%, which makes it difficult to play a decisive hydrophobic performance on the sample surface.…”

“…In general, high roughness and low surface energy are the keys to obtaining superhydrophobic surfaces [21]. For the modulation of the surface wettability of the stone components, one method is to keep the samples in air for a long time to obtain high hydrophobicity after processing the micro-nano structures [31], and the other is to add hydrophobic coatings on the surface [27]. After we process and characterize the femtosecond laser grooving samples with different groove spacing, we also further analyze the corresponding wettability.…”

“…It was concluded that the laser processing triggered two different effects: an "initialization" of the chemical state of the surface that turns much more reactive (likely because of the thermal decomposition of CaCO 3 at the near-surface of the laser-treated region) and an increase in the surface-to-volume ratio, favoring the extent of incorporation of water (hydroxylation) and (likely) C-H contaminants. Eventually, the WCA was able to stabilize at approximately 140 • after close to 8-11 months [31].…”

“…Ultrafast lasers are also able to form selective cold ablations, which allow for an overall higher processing quality [28]. In this context, the ultrafast laser processing method is also an alternative use in the preparation of superwetting structures on stone material surfaces [29][30][31]. As early as 2019, Ana J. López et al [30] processed structures, such as grooves and holes, by femtosecond laser on the marble (Crystal White) surface and explored the corresponding wettability.…”

“…It is also suggested that the ultrafast laser prepared air pockets between the marble surface and water droplets by processing a hierarchical structure, thus realizing hydrophobic behavior [30]. Drawing on the superhydrophobic structure on the surface of a lotus leaf, in 2022, Rocío Ariza et al [31] processed similar micro-nano structures on the marble surface by grooving with a femtosecond laser. A femtosecond laser with a repetition rate of 500 kHz was adopted to maximize the nonlinear absorption and heat accumulation effects.…”