We have prepared a composite thin coating by incorporation of CuFe2O4/Cu2O/CuO nanoparticles in polymethyl methacrylate (PMMA) matrix by using the solution casting method. The electrical explosion of two twisted wires (EETW) was used to obtain multicomponent CuFe2O4/Cu2O/CuO nanoparticles with an average particle size of 20–70 nm. The microscopic studies showed that the nanoparticles in the composite coatings are evenly distributed. However, nanoparticles are strongly agglomerated as the powder concentration in the coating increases to 5 wt.% and 10 wt.%, as the size of particle agglomerates increases to 50 and 100 μm, respectively. Therefore, nanoparticles were pre-treated with ultrasound when introduced into the PMMA matrix. The thermal stability of the composite coating does not change with the introduction of CuFe2O4/Cu2O/CuO nanoparticles in the amount of 5 wt.%. The inclusion of nanoparticles in the PMMA matrix significantly enhances its antibacterial activity. The addition of 5 wt.% nanoparticles inhibited the growth of E. coli by 100% and the growth of MRSA by 99.94% compared to pure PMMA already after 3 h of exposure of bacteria on the surface of the composites. This research provides an easy-to-manufacture and cost-efficient method for producing a CuFe2O4/Cu2O/CuO/PMMA composite coating with a broad application as an antibacterial material.
The paper studies patterns of interaction of electroexplosive Co nanoparticles with air oxygen during heating. The characteristics of Co nanoparticles and composite Co/CoO/Co3O4 nanoparticles formed as a result of oxidation were studied using transmission electron microscopy, X-ray phase analysis, thermogravimetric analysis, differential scanning calorimetry, and vibrating sample magnetometry. It was established that nanoparticles with similar morphology in the form of hollow spheres with different content of Co, CoO, and Co3O4 can be produced by varying oxidation temperatures. The influence of the composition of composite nanoparticles on their magnetic characteristics is shown.
Biocompatible poly(lactide-co-glycolide) scaffolds fabricated via electrospinning are having promising properties as implants for the regeneration of fast-growing tissues, which are able to degrade in the body. The hereby-presented research work investigates the surface modification of these scaffolds in order to improve antibacterial properties of this type of scaffolds, as it can increase their application possibilities in medicine. Therefore, the scaffolds were surface-modified by means of pulsed direct current magnetron co-sputtering of copper and titanium targets in an inert atmosphere of argon. In order to obtain different amounts of copper and titanium in the resulting coatings, three different surface-modified scaffold samples were produced by changing the magnetron sputtering process parameters. The success of the antibacterial properties’ improvement was tested with the methicillin-resistant bacterium Staphylococcus aureus. In addition, the resulting cell toxicity of the surface modification by copper and titanium was examined using mouse embryonic and human gingival fibroblasts. As a result, the scaffold samples surface-modified with the highest copper to titanium ratio show the best antibacterial properties and no toxicity against mouse fibroblasts, but have a toxic effect to human gingival fibroblasts. The scaffold samples with the lowest copper to titanium ratio display no antibacterial effect and toxicity. The optimal poly(lactide-co-glycolide) scaffold sample is surface-modified with a medium ratio of copper and titanium that has antibacterial properties and is non-toxic to both cell cultures.
This article dwells upon the additive manufacturing of high-energy materials (HEM) with regards to the problems of this technology’s development. This work is aimed at identifying and describing the main problems currently arising in the use of AM for nanostructured high-energy materials and gives an idea of the valuable opportunities that it provides in the hope of promoting further development in this area. Original approaches are proposed for solving one of the main problems in the production of nanostructured HEM—safety and viscosity reduction of the polymer-nanopowder system. Studies have shown an almost complete degree of deagglomeration of microencapsulated aluminum powders. Such powders have the potential to create new systems for safe 3D printing using high-energy materials.
Electrical explosion of aluminum wires has been shown to be a versatile method for the preparation of bimodal nano/micro powders. The energy input into the wire has been found to determine the relative content of fine and coarse particles in bimodal aluminum powders. The use of aluminum bimodal powders has been shown to be promising for the development of high flowability feedstocks for metal injection molding and material extrusion additive manufacturing.