Flexible sol-gel coatings on polymeric and metallic materials

One of the current forefront in the field of photonic are flexible photonic research and development. The desired deliverable is to adjust the mechanical properties of materials to fabricate flexible photonic systems with various applications, e.g. gratings, channel waveguides, solar cells, protective coatings. It is well known that sol-gel metal oxide coatings may find applications as flexible coatings in photonics. Moreover, these materials can be easily functionalized to obtain materials with additional special, desired, properties like easy-to-clean, anti-fingerprint, anti-fogging and others, what is attractive for the potential of future commercialization of flexible photonic materials. In this work, we present the first step of research aimed to obtain silica-based coatings with appropriate adhesion on flexible substrates as poorly wettable surface - polymer PET and Ti-6Al-4V and 316L metallic thin foil as active oxide surface. The use of various types of substrates was aimed at presenting diversity in the possibilities of using the proposed coating materials. Nanoindentation, tensile test and scratch test of the investigated samples were studied. Measuring the mechanical properties of thin oxide films is difficult because it is usually impossible to detach of coating, not destroying its, from substrates. The thickness of coatings can range from a dozen to a few hundred nanometres, so complete methodology to determine a full set of mechanical properties is still lacking. In literature, the surface of samples is measured without a clear indication on coating properties, but on features which are the results of substrate-coating combinations.