Characterisation of Antibacterial Surface Textures on Titanium Alloys

Surface modification of metallic materials to impart antibacterial properties has attracted significant attention for practical applications in biomedical and industrial fields. This study aims to characterise the antibacterial surface textures of Ti alloys (Ti-6Al-4V) and investigate their relationship with water repellency, bio-adhesion resistance, and antibacterial performance. Two distinct surface textures were fabricated using chemical (acid treatment for 5 and 20 min) and physical methods (tensile testing). Antibacterial tests revealed 41.6%, 14.6%, and 31% reductions in the viable bacterial counts for the 5-minute acid-treated, 20-minute acid-treated, and tensile-tested samples, respectively, compared to untreated controls. Contact angles of 100.9°, 96.1°, and 79° were observed, indicating varying degrees of water repellency. The acid-treated samples exhibited reduced bio-adhesion, whereas the tensile-tested samples showed increased bio-adhesion. These findings suggest that the surface morphology that inhibits bacterial aggregation is the primary factor contributing to antibacterial properties. Although water repellency and bio-adhesion resistance are often associated with antibacterial surfaces, they serve as functional correlations rather than direct determinants. The surface texture developed in this study exhibited a symmetrical vertical height distribution with Sa = 0.24 µm and featured flat valley regions, rendering it highly suitable for antibacterial applications and promising for use in biocompatible environments.