Sergey Kapustin

A two-layer superhydrophobic coating consisting of a heating and water-repellent layer is obtained. The heating layer, which is a percolation network of carbon nanotubes (CNTs), is reinforced with a polymer to improve surface adhesion, strength, and wear resistance. Epoxy resin is used as a reinforcing polymer. Various methods of organizing a heating layer from CNTs with a reinforcing polymer are considered, and the best ones are identified for creating a heating or antistatic surface. The influence of the concentration of CNTs in the polymer on the strength of the composite is studied. Different methods of introducing nanotubes in the polymer are compared to achieve the best deagglomeration of nanoparticles. The effects of functionalization of nanotubes are tested, and an increase in the coating strength with a slight increase in conductivity is revealed. The optimal concentration of Taunit-M carbon nanoparticles for strengthening ED-20 epoxy resin is found to be 0.07% for nonfunctionalized nanotubes and 0.5–0.6% for particles with –CONH₂ in groups. It is possible to achieve a superhydrophobic state of the surface: the contact angle of wetting is 152.3 ± 0.7 and the angle of the beginning of the sliding of the droplet is 1.6 ± 0.9.

The creation of a multifunctional coating based on carbon nanomaterials, in particular one with protective biocidal properties, is considered a promising direction. The protection of material surfaces from destruction by micromycetes-destructors is of particular interest. The study presents data on the interaction of nanomaterials of the Taunit-M brand (multiwalled carbon nanotubes), onion-shaped carbon nanostructures, and Tuball (single-walled carbon nanotubes) with micromycetes-destructors. The aim of this paper is to study the influence of these materials used in the coating composition on the processes of surface overgrowth by micromycetes-destructors. The growth of the Penicillium chrysogenum strain (Cs/21) and Aspergillus niger strain (Ch4/07) on pure carbon nanotubes, nanotubes functionalized with –OH, –COOH, and –CONH₂ groups, as well as carbon nanotubes decorated with onion-shaped carbon nanostructures, detonation nanodiamonds (DNDs), and titanium dioxide nanocrystals, is studied. The samples are made in the form of a superhydrophobic coating of nanoparticle-based xerogel. The highest resistance is demonstrated by coatings made of functionalized multiwalled carbon nanotubes of the Taunit-M brand with –OH, –COOH and CONH₂ groups, as well as those decorated with titanium dioxide and DNDs. The development of micromycetes on their surface is absent in all test variants. These coatings do not contain food sources for micromycetes, but contain components with biocidal properties. Thus, they can be considered biostable. The studied carbon nanomaterials are proposed to be used for the organization of protective superhydrophobic coatings, since they are produced in industrial quantities and are easily accessible for comparative studies.

A study on the dependence of the thermal conductivity of the percolation network of carbon nanotubes (or CNTs) on the type and degree of functionalization has been carried out. The study was focused on the influence of the more commonly used -COOH, -OH and -СОNH2 groups. A non-linear dependence of the conductivity on the number of functional groups has been revealed. A small number of functional groups can improve conductivity, and a large one can impair it. We presuppose the existence of competing processes that increase thermal conductivity (changes in the CNT geometry, improvement of the contact between them) and enhance photon scattering (emergence of defects and scattering centers). The data can be used for controlling the thermophysical properties of the CNTs as well as determining the optimal degree of functionalization during the development of composites and nanodevices.

A method is proposed for increasing the resistance of a superhydrophobic coating based on a CNT xerogel to frost deposition through the use of decorating nanoparticles. The effects of the addition of fullerenes, carbon nanoonions (CNOs), detonation nanodiamonds, silicon dioxide, and paraffin to the xerogel are tested. An increase in the resistance of the coating to the deposition of condensate in the form of frost is revealed. The addition of fullerene C₆₀ leads to the best results. Increasing the resistance to icing allows us to spend less power on heating the surface during short cold snaps, bypassing the anti-icing properties of the protective superhydrophobic layer. However, the application of this approach shows a deterioration in the resistance of the coating to the penetration of the spray. This is given a qualitative explanation and measures to combat it are proposed. No effect of the additives on the mechanical properties of the coating or its resistance to damage is detected. In additon, decorating additives affect the formation of the coating relief. With this, it is possible to influence the stochastic processes of the formation of roughness during the drying of the xerogel.

The previous article introduced the idea of a superhydrophobic coating from carbon nanoparticles that can combine the lotus effect, the slip effect and electric current heating. A further development of this idea was suggested. The article demonstrated the possibility of a practical implementation of the suggested approach using two coating layers—the electro-thermal layer from carbon nanotubes and the water-repellent layer from onion-like carbons. This coating allows to conserve energy during periods of slight cooling simply due to the use of the lotus effect. The heating is used to prevent icing at lower temperatures. The best contact angle achieved equals 155.9 ± 0.5 degrees at a slip start angle of 1.2 ± 0.5 degrees.

For the first time, a superhydrophobic coating based on onion-like carbon was synthesized by an economically feasible and scalable method was obtained. Two simple and easily reproducible methods of application are proposed. The possibility of using such coating to detect the composition and humidity of the air as well as its anti-icing properties are studied.

The creation of hydrophobic anti-icing and self–cleaning coatings is a relevant task for many industrial sectors. The potential field of application includes production of liquid and gas separators and filters, the field of textiles and clothing, construction and new materials, optical and microelectronic devices, the field of automobile construction and maritime shipping as well as energy and agriculture. The article suggests a new approach to the creation of superhydrophobic anti-icing coatings, by drawing peeled multi-walled carbon nanotubes (MWCNTs) to the sample surface. This method allows you to combine the necessary factors: Low surface energy, micro-nano-roughness and hierarchical multi-scale. The authors investigated the dependence of the wetting angle of such a surface on the model of MWCNT, fractional composition and the polarity of the dissolvent. The suggested approach can be used to create superhydrophobic coatings with the additional function of removing static charge and heating the surface, which can be used in the field of energetics for protection against freezing of wind turbine blades and aircraft surfaces.

The creation of hydrophobic, antifreeze and self-cleaning coatings is currently being pursued by many industrial sectors. The potential applications include the production of liquid and gas separators and filters, new materials, optical and microelectronic devices, and textiles and clothing. These coatings will also have wide application in the construction and automobile industries, shipping, and energy and agricultural sectors. The article proposes a simple approach to the creation of superhydrophobic and antifreeze coatings, by applying powder from multi-walled carbon nanotubes (MW-CNTs) to the sample surface. This method enables combination of the necessary factors: low surface energy, micro–nano-roughness and hierarchical multi-scale. The authors investigated the dependence of the wetting angle of such a surface on the time, type and degree of functionalization. The electrophysical properties of modified MW-CNTs were studied over wide frequency and temperature ranges. This method of obtaining hydrophobic coatings differs from currently available methods in that it is simpler to prepare, is of lower cost and has less environmental impact. The proposed approach can be used to create superhydrophobic coatings that have the additional function of removing static charge and therefore reducing surface heating, and which can be used in the field of energetics for protection against the freezing of wind turbine blades and aircraft surfaces.

A theory is developed for the ion sputtering of metals resulting in the formation of excited neutral and charged clusters with their subsequent fragmentation to a stable state. The effect...