Formation of hierarchical micro/nanostructures of Ag/sodium titanate on grade 2 titanium via hybrid laser/hydrothermal processing

Abstract

Nowadays, titanium implants with multi-scale surface geometries exhibiting biomimetic and antibacterial properties have garnered significant attention due to their potential to enhance osteoconduction and osseointegration. Although titanium is inherently bioinert, surface modification has transformed it into one of the most biocompatible materials for implants. This study aimed to create and characterize a multi-scale geometric surface on grade 2 titanium samples, simultaneously alloyed with silver, using a hybrid laser/hydrothermal process. The effects of laser parameters on surface morphology, roughness, and wettability were evaluated for both surface-alloyed and unalloyed samples. The results showed that laser treatment created regular micrometer-scale structures with controllable silver incorporation. Subsequent hydrothermal treatment further modified the surface by forming a nanoscale Ag/sodium titanate structure on the laser-induced micro-roughness, significantly enhancing wetting behavior and resulting in a superhydrophilic surface. Moreover, increasing the laser groove line spacing altered the surface micro/nanostructure morphology, leading to the formation of a silkworm-like titanate structure. Additionally, the S_q and S_a roughness parameters decreased with increasing laser groove line spacing, while S_sk < 0 and S_ku < 3 values were obtained, potentially contributing to long-term surface wettability.