Tuesday 10 december 2019 16:00 – 17:00 A. Payatakes Seminar Room
” Advanced femtosecond beam tailoring for generation of functional biomimetic textures on metallic surfaces ”
Dr. Fraggelakis Fotis Institute of Electronic Structure and Laser (IESL)
Abstract
A vast gamut of functional surfaces that exhibit extraordinary properties can be found in nature. Derived after millions of years of evolution, those surfaces incorporate the successful result of an almost infinite number of trials and hold a potential to make a real breakthrough for material applications in our everyday life. Among those functionalities are, superhydrophobicity, antireflectivity, wear reduction and omniphobicity. Several of the properties of natural surfaces match demands for functional surfaces in materials industry. From everyday applications like antireflective smartphone screens to antibiofouling medical tools and frictionless metals in automotive industry, the necessity to design materials with tailored surface properties becomes more and more prominent. Femtosecond laser surface texturing already proved its value in mimicking bioinspired functionalities. Nevertheless, despite the progress to date in laser texturing, mimicking the extraordinary variety and complexity of natural surfaces at the nanoscale, i.e. beyond the light diffraction limit, is far from being accomplished. Indeed, functional surfaces found in nature comprise a broad range of characteristic sizes often near or even well below the microscale and exhibit complex hierarchical morphologies with multiple axes of symmetry. On the contrary, the Laser Induced Periodic Surface Structures (LIPSS), which can be induced in almost any solid surface, exhibit single-axis symmetry, while their period is close to or higher than the laser’s wavelength used for texturing. In the presented work we combine state of the art techniques like temporal and spatial beam shaping to enable the desired level of control over the laser induced nanostructure’s symmetry and
directionality, particularly beyond the diffraction limit, for the fabrication of complex hierarchical biomimetic structures on metallic surfaces.