The study involved research on two types of nanocomposite coatings based on polysiloxane and multiwalled carbon nanotubes (MWCNTs). The coatings were made using the same steel substrate while they were obtained by two different methods: sequential and co-deposition method. Spectroscopic measurements using Raman and infrared spectroscopy, as well as microscopic examination and wettability tests, were applied to examine structure, microstructure and physical properties of the obtained layers. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) were used to characterize the coatings from the point of view of their corrosion resistance. The Raman confocal spectroscopy provided valuable data explaining the behavior of carbon nanotubes in the polymer matrix and allowed to distinguish structural differences in the two analyzed layers. The results obtained for nanocomposite coatings were compared with the results obtained for coatings made on the basis of their individual components, namely the coating consisting of pure carbon nanotubes as well as those obtained from pure polysiloxane. Based on the applied methods, an attempt to explain the differences in the corrosion resistance of four types of coatings was made.

The aim of this work was to synthesize porous ceramic materials from the SiOC system by the sol-gel method and the subsequent pyrolysis. The usage of two types of precursors (siloxanes) was determined by Si/C ratio in starting materials. It allows us to control the size of the pores and specific surface area, which are crucial for the potential applications of the final product after thermal processing. Methyltrimethoxysilane and dimethyldiethoxysilane were mixed in three different molar ratios: 4:1, 2:1, and 1:1 to emphasize Si/C ratio impact on silicon oxycarbide glasses properties. Structure and microstructure were examined both for xerogels and obtained silicon oxycarbide materials. Brunauer-Emmett-Teller (BET) analysis was performed to confirm that obtained materials are porous and Si/C ratio in siloxanes precursors affects porosity and specific surface area. This kind of porous ceramics could be potentially applied as gas sensors in high temperatures, catalyst supports, filters, adsorbents, or advanced drug delivery systems.

Nanocomposites developed based on siloxanes modified with carbon nanoforms are materials with great application potential in the electronics industry, medicine and environmental protection. This follows from the fact that such nanocomposites can be endowed with biocompatibility characteristics, electric conductivity and a high mechanical durability. Moreover, their surface, depending on the type and the amount of carbon nanoparticles, may exhibit antifouling properties, as well as those that limit bacterial adhesion. The paper reports on the properties of polysiloxane (PS) and carbon nanotubes (CNT) nanocomposite coatings on metal surfaces produced by the electrophoretic deposition (EPD). A comparison with coatings made of pure PS or pure CNT on the same substrates using the same deposition method (EPD) is provided. The coatings were examined for morphology and elemental composition (SEM, EDS), structural characteristics (confocal Raman spectroscopy), electrical conductivity and were tested for corrosion (electrochemical impedance spectroscopy-EIS, potentiodynamic polarization-PDP). The results obtained in this study clearly evidenced that such hybrid coatings conduct electricity and protect the metal from corrosion. However, their corrosion resistance differs slightly from that of a pure polymeric coating.

The nanocomposite coatings composed of carbon nanotubes and various forms of copper were prepared in the two-step process. Firstly, carbon nanotubes were coated on stainless steel substrate using electrophoretic deposition at constant current. Then, the process of electrochemical deposition using copper(II) sulphate solutions was performed under high overpotential conditions. The modification of the copper(II) cations concentration in the solution and the deposition time provided the formation of various forms of crystals. The samples and their cross-sections were observed and examined using scanning electron microscope equipped with electron dispersive spectroscopy system. The analysis of chemical composition revealed that in addition to the pure copper crystals, the crystals characterized by the presence of copper and oxygen were formed. Therefore, Raman spectroscopy was applied to determine the unknown stoichiometry of this copper oxide. The point and in-depth analysis identified copper(I) oxide in the form of different size crystals depending on the concentration of the copper(II) sulphate solution. To confirm these findings, grazing incidence X-ray diffraction measurements were also performed. the combination of the applied methods has provided the detailed description of the preparation of the nanocomposite coatings with the proposed mechanism of copper(I) oxide formation.

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