This investigation focuses mainly on applied and fundamental research in a very relevant and important area - the corrosion protection of the most widely used metal materials such as structural steels. The latter are often subject to serious corrosion attacks, resulting in a number of economical damages, energy and material losses. The main objective is to create effective protective corrosion-resistant coatings or coating systems of various types on steel by: (1) Forming innovative sol-gel coatings [1] for galvanized steel - doped and /or undoped oxide coatings (single or multi-component), applied sequentially on galvanized steel at different thicknesses of the zinc coating; (2) Obtaining hybrid zinc coatings [2-4] with embedded polymeric based particles or corrosion inhibitors into the metal matrix; and (3) Developing environmentally friendly conversion coatings for galvanized steel [4]. Present investigations demonstrate some general ideas and possibilities for improving the protective properties of the ordinary zinc coatings by applying of materials which are non-toxic and non-harmful to the environment. The experimental techniques and apparatus used to achieve the end goals are: electrochemical methods for characterizing the protective properties (PD curves, polarization resistance - Rp, electrochemical impedance spectroscopy - EIS), XRD analysis, XPS analysis, SEM, TEM, etc.
Keywords:Actuality of the research is determined by needs of modern optics and electronics, because it is well known that modern technologies for the vast majority of electronic and optoelectronic devices, both for household and special purpose, are based on materials harmful to humans and environment. Further development of heterostructures based on traditional materials is limited by the need to harmonize the properties of individual components at the interface. Such limitations are not principal for hybrid composites, where the matrix and its filling components (fillers) interact relatively "weakly" with each other. Then, "strong" interactions within the components provide their stability, while "weak" - allow to find the combinations of components providing necessary properties of a composite as a whole [1].
We described here hybrid composite materials based on natural polymer matrix (micro/nanosized cellulose, MC/NC) incorporated with three types of fillers: microcrystalline cellulose (MCC), graphene oxide (GO), and nanosized dielectric oxides (DO). The fillers should improve or modify, each in its own direction, the properties of the matrix, and they should bring to the composite their own properties uncharacteristic to matrix. Short review about background of this science direction was given (see, e.g. [2, 3]).
New data obtained in our R&D team about cellulose composites are described. Simple oxides (ZnO, ZrO2 nanopaticles co-doped with europium and fluorine ions) as well as complex oxides (bismuth and lanthanum phosphates doped with luminescent RE ions) were incorporated into MC/NC matrix. Morphology, moisture resistance, conductivity, dielectric, optical absorption and luminescence properties of the composites have been studied and analyzed together with data about of starting components properties [4].
Obtained results confirmed the perspectives of practical use of the composites under study.
Biomass is a sustainable and renewable source of valuable monomers. However, the number of monomers that can be obtained from biomass processing is rather limited. In addition, the recycling of used polymeric materials is still challenging.
Here, a sustainable strategy of bio-based polymers recycling was described. First, a series of vinyl ethers was obtained from selected terpenols according to the well-established procedure for vinylation with calcium carbide [1-4]. Further, from the obtained monomers, the corresponding polymers were synthesized by standard procedures. Polymers possessed a certain plasticity and thermal stability, which made it possible to melt them repeatedly without decomposition and changes in properties. After cooling, the polymers became solid again and retained their shape.
The obtained polymeric materials were heated under inert atmosphere at different temperatures (pyrolysis) [5]. It was found that the pyrolysis products under certain conditions were only the starting alcohols (terpenols) and the corresponding aldehydes or ketones. It should be noted that all pyrolysis products are natural compounds.
After pyrolysis, the resulting liquid mixtures were collected and reduced with sodium borohydride. Thus, the corresponding ketones and aldehydes were again converted into the starting alcohols. The yields of these processes were quantitative. Thus, the mixture after the pyrolysis and reduction consisted the starting alcohol. The alcohol was again vinylated with calcium carbide, and then vinyl ethers and corresponding polymers were again obtained. The properties of the re-obtained polymers were found to be the same as initially. Thus, the resulting polymer materials can be recycled many times after the end of life.
In presentation, the synthetic and analytical data will be presented (TGA, DSC, NMR, etc.), characterizing the properties of the obtained compounds and polymers.
This work was supported by the Russian Science Foundation (21-73-20003).
To date, numerous studies have been focused on the self-assembly of petroleum-based block copolymer systems for potential applications in multidisciplinary fields, such as nano-organized films for biosensors, or nanolithography, etc. Such materials are derived from fossil resources that are being rapidly depleted and have negative environmental impacts. In contrast, carbohydrates are abundant, renewable and constitute a sustainable source of materials. This is currently attracting much interest in various sectors and their industrial applications at the nanoscale level will have to expand quickly in response to the transition to a bio-based economy. The self-assembly of carbohydrate BCP systems at the nanoscale level via the bottom-up approach, has allowed only recently the conception of very high-resolution patterning (thin films with sub_10nm resolution) that has never been attained to date by petroleum-based molecules and provides these new materials with novel properties such as: New generation of Nanolithography, Memory devices, OPV, high resolution Biosensors. We will present recent results on the self-assemblies of carbohydrate-based block copolymer leading to highly nanostructured thin films (sub-10nm resolution) using DSA approach in combination of solvent and/or thermal annealing as well as new and ultra-fast microwave “cooking” approach”.(1-6)
Keywords:The use of refractory materials is fundamental in steel mills due to the equipment used in the process of working under high temperatures [1]. For this equipment to perform well and mitigate damage, it is necessary to be coated with appropriate refractory materials so that they are thermally insulated. When rolling hot strips, plate reheating ovens generally use refractories (walls, ceilings, sills, doors, stringers, poles, etc.) [2]. The detonating doors of these ovens require special attention because they are in an aggressive, high-temperature environment [3]. The dry door is an alternative to replace refrigerated doors, to eliminate the recurrent problems of these, with leaks and frequent maintenance, and increase the life of the deformation doors. The use of dry door in reheating ovens of Arcelor Mittal has been advantageous, a study on its application and lifetime shows the efficiency of this port concerning others used.
Keywords:High resolution X-ray diffractometry is the primary structural method used in the investigations of epitaxial layers and structures. In high resolution configuration a 4-bounce Ge(220) Bartels monochromator gives an incidence beam divergence of 12 arcsec. In the diffracted beam path, open detector configuration is used for rocking curves (RC) measurements or triple-axis analyser crystal before the detector is used for reciprocal lattice maps (RLM) measurements. Such configurations allow investigations of the single crystals semiconductor structures including: low-dimensional quantum well (QW), quantum dots (QDs) of lasers, LEDs and solar cells structures. The analysis of the results such as RC and RLM allow determination of the basic parameters of the structure: thickness and composition of the layers, degree of relaxation, lattice parameters, size of crystalline blocks and mosaicity of the highly mismatched structures but also dislocations density and strain in the epitaxial layers. In such analysis the main problem is the measurement of planes perpendicular to the sample surface. In standard XRD configuration it is practically impossible to measure such planes for such highly oriented samples. In order to avoid this problem, planes with a large inclination angle, (e.g. over 60 deg) are investigated using the skew geometry. The application of measurements carried out from the edge of the sample allows analysis of such structures, above all, spatial separation of the effects shown in the investigation results. In particular, it allows independently determination of the lattice parameter perpendicular to the growth direction, separation of tilt and twist mosaicity [1], calculation of the edge dislocations density [2] or residual strains in the structure. Furthermore, such type of measurements reveals the difference in lattice parameters of the specific layers [3], which are not always visible with conventional measurements performed from the surface of the sample. This type of measurements were developed in Structural Research Laboratory in Wroclaw University of Science and Technology and has been used in the analysis of epitaxial structures - mainly mismatched III-N materials like (Ga, Al)N, low dimensional structures (QW and QDs) of the III-V materials but also (Zn,Cd)Te superlattices.
Keywords:The rapid emergence of antibiotic resistance has weakened the efficacy of conventional antibiotics where urgent actions are necessary to address this issue [1]. Nanoparticles have been increasingly explored to nullify this antibiotic resistance and eliminate bacterial cell [2]. However, toxicity issue of nanoparticles coupled with its inability to bypass bacterial cell membrane remain an alarming issue. In this regard, bacteria-derived extracellular vesicle (EV) cloaked nanoparticles can resolve all the mentioned issues due to its natural cellular functions and potential for various biomedical applications [3]. Herein, we report a fabrication of a novel biocompatible anti-Stapylococcus nanoplatform MZL, in which MoS2-ZnO (MZ) nanocomposite (core) was camouflaged with Lactobacillus paracasei-derived EVs (shell) (L). A low-temperature solution synthesis method was utilized to prepare ZnO nanoparticles that were immobilized onto PEG functionalized MoS2 nanosheets. The resulting MZ nanocomposite was characterized using X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. Moreover, the MZL was characterized with hydrodynamic sizes, surface zeta potentials, SDS-PAGE gel analysis. The MZL nanoplatform showed excellent synergistic antibacterial activity against S. aureus compared to other samples and completely eradicates bacteria even at 6.25 µg mL-1 concentration. Additionally, the MZL also showed good biocompatibility. Overall, the proposed EV-coated nanoplatform showed excellent efficacy for antibacterial activity compared to other conventional antibiotic and has the potential for future in vivo application.
Keywords:Tuning the nanoparticle features by doping iron impurities is an interesting field. It provides a tool for structural and optical characteristics controlling for the material. PVA/PbS nanoparticles synthesized by chemical bath route in the presence of PVA polymer as jell bed stabilizer them Sn and Ag ions injected in material as impurities. Prepared samples investigated by XRD and TEM for criticality and morphology proofing, which were in agreement with each other. Optical spectroscopy of nanocomposites studied by Uv-Vis (300-900 nm) range absorption spectra and by using tach relation bandgap of samples was measured that was obviously a semiconductor (around 2.3-2.8 eV). Studying followed by photoluminescence spectroscopy (PL), we saw in this case for both impurities PL quenched by doping. Nonlinear measurements were done by Z-scan technique with a He-Ne CW laser by 632.8 nm wavelength beam focused by 150mm focal length lens was used for exciting samples which led to thermal nonlinearity mechanism. For nonlinear refractive index and nonlinear absorption, self-focusing and saturable absorber attribute were observed respectively. n2 and β were from the order of 10-9 and 10-3, respectively.
Keywords:“The world needs to act fast to avoid catastrophe effect on earth”, suggested by the IPCC 2021 report on climate change. It’s a code red for humanity to survive, evidenced by the recent extreme heatwaves, unusual floods, droughts and rise in temperature. The only possible way to stop this by being sustainable in human activities at home, public places, Institutions and at industry. Most of the time, human and industrial activities affect the environment due to large scale and commercial activities. Suppose the precursors are environmentally friendly in chemical industries. In that case, the manufacturing technique and end use of the product can be sustainable, and it can play a significant role in reducing the carbon footprint. The surge in the sustainable synthesis of nanomaterials and methods is recognized in the last couple of years.
In this talk, I will present promising results in graphene synthesis with the help of natural surfactants. The quality of the nanosheets produced is on par and above the quality of commercial samples. The major problem with reported and commercial surfactants resources is its inability to produce micron-sized graphene with fewer defects, a minimal amount of surfactant, and less toxicity [1-2].
After analyzing the samples with electron microscopy and Raman spectroscopy techniques, we found that nanosheets are defect-free, transparent, thin, and laterally with micron-sized dimensions. Exfoliated graphene is impregnated in low-density polyurethane (PU) foam with open-shell structures and demonstrated for strain sensor and oil-water separation applications. In addition, naturally occurring clay minerals are potential 3D precursors with wide varying thermal properties [3].
Our results stress that natural surfactants are feasible and reliable to produce high-quality graphene and 2D materials, essential in sustainable and scalable manufacturing technologies.
“The world needs to act fast to avoid catastrophe effect on earth”, suggested by the IPCC 2021 report on climate change. It’s a code red for humanity to survive, evidenced by the recent extreme heatwaves, unusual floods, droughts and rise in temperature. The only possible way to stop this by being sustainable in human activities at home, public places, Institutions and at industry. Most of the time, human and industrial activities affect the environment due to large scale and commercial activities. Suppose the precursors are environmentally friendly in chemical industries. In that case, the manufacturing technique and end use of the product can be sustainable, and it can play a significant role in reducing the carbon footprint. The surge in the sustainable synthesis of nanomaterials and methods is recognized in the last couple of years.
In this talk, I will present promising results in graphene synthesis with the help of natural surfactants. The quality of the nanosheets produced is on par and above the quality of commercial samples. The major problem with reported and commercial surfactants resources is its inability to produce micron-sized graphene with fewer defects, a minimal amount of surfactant, and less toxicity [1-2].
After analyzing the samples with electron microscopy and Raman spectroscopy techniques, we found that nanosheets are defect-free, transparent, thin, and laterally with micron-sized dimensions. Exfoliated graphene is impregnated in low-density polyurethane (PU) foam with open-shell structures and demonstrated for strain sensor and oil-water separation applications. In addition, naturally occurring clay minerals are potential 3D precursors with wide varying thermal properties [3].
Our results stress that natural surfactants are feasible and reliable to produce high-quality graphene and 2D materials, essential in sustainable and scalable manufacturing technologies.
