Laser-induced wettability alteration in limestone rocks

• Published in: Materials today communications Vol. 17; pp. 332 - 340
• Main Authors: Sharma, Keerti Vardhan, Nicolini, João V., de Araujo, Olga M.O., Straka, Robert, Ferraz, Helen C., Lopes, Ricardo T., Tavares, Frederico Wanderley
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-12-2018
• Subjects: Contact angles; Fluid-rock interface; Laser-rock interaction; Limestone; Surface roughness; Wettability; Contact angles; Limestone; Wettability; Surface roughness; Fluid-rock interface; Laser-rock interaction
• ISSN: 2352-4928; 2352-4928
• DOI: 10.1016/j.mtcomm.2018.09.012

[Display omitted]
•Limestone surface was engineered by laser to tune its wettability properties.•Nd:YAG laser reduced the surface roughness of limestone by 2 μm.•Nd:YAG treatment transformed the limestone surface from hydrophillic to hydrophobic.•Laser treated limestone exhibited reduced contact angle for black oil/seawater interface.
Alteration of wettability is pre-eminent in improving the efficiency of various industrial applications related to the materials such as metals, polymers, and rocks. We demonstrate wettability alteration in limestone porous rocks using different lasers with different wavelengths and energy. In addition to the chemical changes induced in rocks, laser treatments with different fluence modify the surface roughness of limestone differently. Pulsed Nd:YAG laser (330 mJ/pulse) reduced the surface roughness of limestone from 12.22 μm to 10.10 μm.
For ultrapure water/air interface, all laser treated limestone surfaces exhibited increased contact angle. Especially, for seawater/air, pulsed Nd:YAG laser increased the contact angle substantially, from 56.75° to 106.6°, changing the surface from hydrophilic to hydrophobic. For crude oil/ultrapure water interface, increase in contact angles were reported for all laser treated limestone samples. But for crude oil/seawater interface, limestone treated with pulsed Nd:YAG laser exhibited a reduced contact angle of oil/limestone, from 29.4° to 13.3°, making the surface even more oleophobic.