Design and development of sustainable nanotechnological protective systems in surface treatment

Hybrid organic‐inorganic nanomaterials, featuring functional nanomaterials (nanofillers) in combination with organic/inorganic polymeric matrices (either based on sol‐gel or synthetic/natural organic polymers), currently find useful applications in many industrial sectors. The main reason stands in the possibility that these innovative materials offer of being chemically/physically modified at a nano‐dimensional level and opportunely functionalized for the treatment of different kind of surfaces to give them final implemented chemical, physical and mechanical properties. In particular, in surface treatments field, the simplest, most efficient and versatile methodology to modify the surface of different materials, with a view to moving towards increasingly sustainable and eco‐friendly materials, thus improving their properties, involves the use of sol-gel based materials to be used as coating systems. Moreover, recent literature also highlights the characteristic properties of nanomaterials and their possible use in the development of widely employed hybrid sol‐gel matrices for the development of useful coatings for corrosion mitigation on different metallic surfaces, as well as hydrophobic and antifouling coatings for different application fields like blue‐growth, buildings, cultural heritage and textiles sector. The research activity of this thesis aims to explore the synthesis of many types of nanostructured coatings and surface finishing, as well as the associated attributes and the most relevant applications. The main goal of this study was to investigate and evaluate many types of sol‐gel coatings that may be applied to various substrates in order to change and improve their surface characteristics. In particular, this thesis was developed and organized into three sections, apt to the kind of materials studied, the employed substrate, the used characterization techniques and, in particular, to the applications in different industrial and environmental sectors. The first section refers to the development and study of chromium‐free nanotechnological systems capable of effectively and durably preventing the corrosion of surfaces in the aqueous phase. Corrosion is one of the primary causes of metal structural degradation over time and even destruction, producing changes in metal products appearance and performances. The second section concerns the design and development of eco‐friendly and innovative fouling release coatings to overcome the biofouling issue. This naturally occurring phenomena is a major economic challenge for marine industries, and considerable attempts have been undertaken in recent decades to develop efficient fouling release surfaces (coatings) that combine advances in materials science and recent knowledge of marine chemistry and biology. The third section focuses on the preparation of sol‐gel based coatings for textile fabrics and evaluation of their hydrophobic properties. Common cotton fabrics samples, which are largely representative of natural fibers, were used to better understand the effect of sol‐gel coatings on the physical properties of textiles systems. The facile synthetic approach of the sol‐gel technique for coating realization could be extended to prepare durable sol‐gel based hybrid coatings on a variety of substrates, thus indicating a powerful technological potential in daily life and extending their employment in several innovative industrial applications.