Wetting behavior investigation of a complex surface prepared by laser processing combined with carbon films coating

Abstract To solve blood adhesion problems on the surface of medical devices, such as scalpel blades and implants, a hydrophobic and serum-repellent surface was prepared and investigated. First, porous ablated surface on stainless steel (SS) was fabricated via laser processing. Then, the laser-ablated SS (LA-SS) surface was covered by thin tetrahedral amorphous carbon (ta-C) films using a filtered cathodic vacuum arc deposition (FCVAD) technique. As such, a complex surface, i.e., a porous LA-SS surface coated with ta-C films (named as LAC-SS surface), was obtained. The morphologies of the LA-SS surface were tailored by adjusting the scanning rate and laser fluence during laser processing. By decreasing scanning rate, an ablated layer with high-aspect-ratio cavities and large roughness can be fabricated. The wetting tests of water and serum droplets indicated that the LAC-SS surface exhibited excellent hydrophobicity and serum-repellency. Under optimal processing parameters, the wetting behaviors of droplets obey the Cassie-Baxter wetting model. An optimal LAC-SS surface was obtained with a water contact angle of 151.4 ± 1.4° and a serum contact angle of 143.0 ± 1.3°. The optimal surface also demonstrates great anti-adhesive properties with a water sliding angle of 14.1 ± 2.2° and a serum sliding angle of 21.7 ± 2.8°. This optimized complex surface can be used in medical devices to address blood adhesion problems.