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The introduction of new regulations needs to develop eco-friendly systems to prevent corrosion. In this work, a natural corrosion inhibitor caffeine (CAF) was encapsulated in polysaccharide-based nanoparticles, capable of the responsive release of CAF during corrosion. The nanoparticles were prepared using electrostatic complexation between two natural polysaccharides which are oppositely charged—chitosan (CHI) and sodium alginate (ALG), crosslinked by tripolyphosphate (TPP). The particle size distribution and zeta potential were evaluated using dynamic light scattering and laser Doppler velocimetry. The encapsulation efficiency and release of CAF from nanocontainers was evaluated with UV-spectroscopy. The nanoparticles were incorporated via electrodeposition into the zinc coating on low-carbon steel to ensure self-healing. Cyclic voltammetry demonstrated the cathodic and anodic processes in the starting electrolytes. Surface hydrophobicity was investigated by water contact angle (WCA). The corrosion resistance of the coatings was estimated with polarization resistance (Rp) measurements and potentiodynamic polarization (PDP) curves. The study of the chemical composition of the coatings was carried out with X-ray photoelectron spectroscopy. The data obtained confirm the indisputable influence of the nanoparticles/nanocontainers on the protective feature of the hybrids—the latter have about twice-higher Rp values compared to the ordinary zinc.

In this paper, hybrid coatings based on ZnO dispersion in water soluble chitosan oligosaccharides (COS) as dispersion medium were prepared. The obtaining procedure of anti-corrosion hybrid zinc-based coatings containing COS coated ZnO particles in the metal matrix has been described. The available ZnO particles coated with COS were observed by TEM and thereafter added to the starting electrolyte for electrodeposition of hybrid zinc coatings on low-carbon steel substrates. The newly developed objects were collated with ordinary zinc coatings concerning the peculiarities of the morphology, topography and hydrophilicity of the surface (SEM and AFM analyses, water contact angle measurements), as well as corrosion behavior and electrochemical characteristics (cyclic voltammetry, potentiodynamic polarization curves, polarization resistance measurements). XRD and XPS methods were applied for studying of the crystallographic structure, as well as chemical and phase composition of the newly appeared corrosion products during the corrosion treatment in the test medium. Protective parameters of the coatings were evaluated in chloride environment of 5% NaCl solution. The results showed the effect of the concentration of the COS coated ZnO particles on the crystallographic structure and on the anticorrosion stability of the hybrid coatings.