Design and characterization of textured surfaces for applications in the food industry

The aim of this work is to design, manufacture and characterize surface morphologies on AISI 316L stainless steel produced by a custom designed laser-texturing strategy. Surface textures were characterized in terms of areal parameters compliant with ISO 25178 and correlations between these parameters and processing parameters (e. g. laser energy dose provided to the material, repetition rate of the laser pulses and scanning velocity) were investigated. Preliminary efforts were devoted to the research of special requirements for surface morphology that, according to the commonly accepted research on the influence of surface roughness on cellular adhesion on surfaces, should discourage the formation of biofilm. The topographical characterization of the surfaces was performed with a Coherence Scanning Interferometer. This approach showed that increasing doses of energy provided to the surfaces increased the global level of roughness as well as the surface complexity. Moreover, the behavior of the parameters Spk, Svk indicates also that, due to the ablation process, an increase in the energy dose causes an average flattening of the hills and of the dales of the surface. The study of the density of peaks Spd showed that none of the surfaces analyzed here seems to perfectly match the conditions dictated by the theories on cellular adhesion to confer antibiofouling properties. However, this result seems to be mainly due to the limits in the resolving power of Coherence Scanning Interferometry, which does not allow to resolve sub-micrometric features expected to be crucial in the prevention of cellular attachment.