Functionalization of surfaces by ultrafast laser micro/nano structuring

In surface functionalization, micro- and nanotexturing with ultrashort pulse lasers is of increasing interest in industry. These two scales of structures can be obtained by a selforganization of the matter after laser irradiation, or by a micro-machining of the sample with successive ablations. Controlling key-parameters such as wavelength, laser fluence, spot overlap, number of repetitions and polarization, allows the generation of self-organized nanostructures called ripples or the creation of square-shaped micro-structures. In the first case, a surface textured with these nano-gratings presents a diffractive aspect or a permanent marking, but changes little the initial wetting behaviour of the surface. In the second case, the microstructures improve significantly the wettability of the surface, with an increase of almost 20° of the contact angle with a water droplet. So a large range of surface texturing can be performed with ultrashort pulsed laser technology, offering a wide range of applications, from biomedical to aeronautical.