Characterization of hydrophobic metasurfaces fabricated on Ni-Mn-Ga-based alloys using femtosecond pulsed laser ablation

The generation of hydrophobic surfaces through laser ablation has garnered considerable attention, particularly for its prospective diverse applications across various industries. This study explores the possibility of generating controllable hydrophobic metasurfaces on Ni-Mn-Ga-based magnetic shape memory (MSM) alloys using femtosecond pulse width laser (FPWL). While hydrophobic surfaces have been achieved on different materials through a variety of different techniques, the research marks the first systematic attempt to tailor hydrophobicity on the surface of Ni-Mn-Ga-based alloys. By characterizing surfaces treated with different laser parameters, the distinct morphologies and hydrophobic properties corresponding to each surface were identified. This newfound control over surface properties with specific machining parameters opens possibilities for applications in microfluidic devices. Additionally, the potential of utilizing the magnetic-field-induced strain (MFIS) exhibited by Ni-Mn-Ga single crystals to alter surface hydrophobicity was explored. Metasurfaces mimicking the dimensional changes in elongation induced by MFIS demonstrated higher static contact angles (SCAs) for water droplets compared to the original surfaces. This approach presents a promising avenue for creating multifunctional microdevices with controllable hydrophobicity using Ni-Mn-Ga-based alloys. Our findings not only offer insights into tailoring of hydrophobic/hydrophilic properties on Ni-Mn-Ga-based MSM alloys but also provide a novel methodology for fabricating functional metasurfaces on other metals.