Wetting behaviour of femtosecond laser textured Ti–6Al–4V surfaces

Abstract

Abstract:The aim of the present work was to investigate the wetting behaviour of biomedical grade Ti-6Al-4V alloy surfaces textured by a femtosecond laser treatment. The material was treated in ambient atmosphere using an Yb: KYW chirped-pulse-regenerative amplification laser with a wavelength of 1030 nm and a pulse duration of 500 fs. Four main types of surface textures were obtained depending on the processing parameters and laser treatment method. These textures consist of: (1) nanoscale laser-induced periodic surface structures (LIPSS); (2) nanopillars; (3) a bimodal roughness distribution texture formed of LIPSS overlapping microcolumns; (4) a complex texture formed of LIPSS overlapping microcolumns with a periodic variation of the columns size in the laser scanning direction. The wettability of the surfaces was evaluated by the sessile drop method using distilled-deionized (DD) water and Hank's balanced salt solution (HBSS) as testing liquids. The laser treated surfaces present a hydrophilic behaviour as well as a high affinity for the saline solution, with equilibrium contact angles in the ranges 24.1-76.2. for DD water and 8.4-61.8. for HBSS. The wetting behaviour is anisotropic, reflecting the anisotropy of the surface textures.

Laser surface textured titanium alloy (Ti–6Al–4V): Part 1 – Surface characterization

“…The contact angle decreases from 60 o for as received sample to 55 o for dimple textured and 50 o for liner textured surface (parallel to grooves direction) and 45 o (perpendicular to grooves direction) degree. Cunha et al [34] showed the wetting behavior is anisotropic, reflecting the anisotropy of the surface textures.…”

Femtosecond laser fabrication of highly hydrophobic stainless steel surface with hierarchical structures fabricated by combining ordered microstructures and LIPSS

“…In order to solve these problems, femtosecond laser micro-nano machining has emerged as an effective technique to create dual scaled surfaces with nano-and micro-structures [17], [18], [19]. Chloroalkylsilane and fluoroalkylsilane coatings are frequently used to greatly decrease the surface energies of the laser machined surfaces and to obtain the highest contact angles [20].…”

Laser Beam Machining, Laser Beam Hybrid Machining, and Micro-channels Applications and Fabrication Techniques

“…Femtosecond laser treatments allow to achieve various surface textures on such biomedical implants. These textures consist of nanoscale laser-induced periodic surface structures (LIPSS), nano-pillars, micro porous columns and complex textures which are nowadays being adopted for implants due to different wettability characteristics [35]. The increase in fluence also alter the microstructure and wear resistance of implants positively in terms of surface grain size and hardness [36].…”