Laser Patterned Titanium Surfaces With Superior Antibiofouling, Superhydrophobicity, Self-Cleaning And Durability: Role Of Line Spacing

Superhydrophobic titanium surfaces with different line spacing (pitch) of 20, 50, 80 and 100 mu m are fabricated using nanosecond laser patterning and their antibiofouling, superhydrophobicity, abrasion resistance and self-cleaning properties are studied. The surface morphology, surface profiles and surface roughness are obtained from scanning electron microscopy (SEM), optical microscopy and surface profilometry. Initially, the dual scale roughness structured laser patterned surfaces were hydrophilic but on prolonged storage time in ambient conditions, average water contact angle (WCA) > 160 degrees was obtained due to the accumulation of atmospheric hydrocarbon compounds on the surface which was confirmed by laser Raman spectroscopy (LRS) and X-ray photoelectron spectroscopy (XPS). The laser patterned titanium samples exposed to the Pseudomonas sp., bacterial culture showed a 4-order reduction in bacterial adhesion as compared to control samples. Furthermore, the superhydrophobic laser patterned samples exhibited excellent water repellency at different ionic strength chloride solutions, photo-catalytic activity under visible light and abrasion resistance. The laser patterned titanium samples are found to regain the superhydrophobicity by replenishing the carbonaceous layer (denuded in organic solvents) on exposure to an open atmosphere for 14 days. This study provides new avenues to engineer the wetting properties of surfaces by varying laser patterning conditions.