Springtail-Inspired Triangular Laser-Induced Surface Textures on Metals Using MHz Ultrashort Pulses

Abstract

Considering the attractive surface functionalities of springtails (Collembola), an attempt at mimicking their cuticular topography on metals is proposed. An efficient single-step manufacturing process has been considered, involving laser-induced periodic surface structures (LIPSS) generated by near-infrared femtosecond laser pulses. By investigating the influence of number of pulses and pulse fluence, extraordinarily uniform triangular structures were fabricated on stainless steel and titanium alloy surfaces, resembling the primary comb-like surface structure of springtails. The laser-textured metallic surfaces exhibited hydrophobic properties and light scattering effects that were considered in this research as a potential in-line process monitoring solution. The possibilities to increase the processing throughput by employing high repetition rates in the MHz-range are also investigated.

Laser engineering of biomimetic surfaces

“…25 below illustrates laser induced morphological profiles for silicon, after static irradiations with cylindrically polarized optical vortexes generated via a q-plate. Furthermore, circularly polarized ultrafast laser pulses are recently utilized to fabricate triangular periodic surface structures on metal surfaces [185,258] which can be used for inducing uniform iridescence of laser structured metallic surfaces.…”

Double- and Multi-Femtosecond Pulses Produced by Birefringent Crystals for the Generation of 2D Laser-Induced Structures on a Stainless Steel Surface

“…Typically, the LSFL period is close to the laser wavelength (λ), while the HSFL period is smaller than λ/2 [10]. A significant step forward to control the structure morphologies, in order to fabricate biomimetic textures [11], was achieved with the production of LSFL having 2D symmetry (2D-LIPSS), thanks to the use of different polarization states of the incident radiation [12,13] and to complex irradiation strategies [14]. Double-pulse irradiation (DPI) has shown the formation of a variety of structures in molybdenum [15] and in steel [16,17].…”

Development of surfaces with antibacterial durability through combined S phase plasma hardening and athermal femtosecond laser texturing

“…Although the substrate material from this study differs from the studies by Romano et al [26,39] (X6Cr17 ferritic stainless steel), the physical characteristics, such as texture periodicity, symmetry and general morphology, appear almost identical, therefore, suggesting similar functional performance is to be expected (Figure 2 & Figure 3). However, wettability testing (functional property) carried out within this study does not follow the same trend as previously observed, with stabilised (3 months) water contact angle readings decreasing following triangular LIPSS texturing of the untreated 316L ASS samples (UntΔ; Table 3).…”

“…Under the right conditions, instead of ripple-like features, triangular shaped and hexagonally organised pillars, resembling the surface of springtails, are formed with similar periodicity to LSFL in 3 different directions [26,39]. Due to the near nanoscale features and high hydrophobicity, these new structures, named triangular LIPSS, are promising for antibiofouling applications, and studies on similar structures have produced excellent results [41].…”

“…The research within the field has evolved from the modifications of macro-and microscale surface topography, to the modification of surface chemistry and more recently to the utilisation of biomimetic (e.g. lotus leaf) and nanoscale structures [24][25][26]. The scientific understanding of the anti-biofouling functional performance of surfaces has also advanced over time, from simple surface hydrophobicity explanations to more complex theories that combine surface wettability (Cassie-Baxter state in particular), surface free energy and surface structure [24,[27][28][29][30].…”