The synthesis and characterization of isotropic magnetorheological elastomer (MRE) with significantly enhanced utility properties is presented. Common drawbacks of classical MREs, such as poor particle wettability, dispersibility, low thermooxidative stability, low chemical stability, and insufficient durability, were eliminated by grafting the carbonyl iron (CI) particles with poly(trimethylsilyloxyethyl methacrylate) (PHEMATMS) using surface-initiated atom transfer radical polymerization (ATRP). Two sets of the MREs were prepared containing bare CI and CI grafted with PHEMATMS chains (CI-g-PHEMATMS). The effects of the coating on magnetorheological behavior in oscillatory shear, as well as the sensing properties of the prepared MREs, were evaluated. The mechanical properties in tensile mode and the particle filler/polydimethylsiloxane (PDMS) matrix interactions were investigated using a dynamic mechanical analysis. The PHEMATMS grafts considerably improved the CI particles' mobility, probably by preventing a partial cross-linking with the PDMS matrix. Besides the plasticizing effect, the MRE containing CI-g-PHEMATMS exhibited moderate mechanical performance and a slightly improved relative magnetorheological effect, but significantly enhanced damping factor, improved magnetostriction, and provided good sensing capability, which make such material highly promising for intended practical applications.

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Development of new types of antibacterial coatings or nanocomposites is of great importance due to widespread multidrug-resistant infections including bacterial infections. Herein, we investigated biocompatibility as well as structural, photocatalytic, and antibacterial properties of photoactive hydrophobic carbon quantum dots/polyurethane nanocomposite. The swell-encapsulation-shrink method was applied for production of these nanocomposites. Hydrophobic carbon quantum dots/polyurethane nanocomposites were found to be highly effective generator of singlet oxygen upon irradiation by low-power blue light. Analysis of conducted antibacterial tests on Staphyloccocus aureus and Escherichia coli showed 5-log bactericidal effect of these nanocomposites within 60 min of irradiation. Very powerful degradation of dye (rose bengal) was observed within 180 min of blue light irradiation of the nanocomposites. Biocompatibility studies revealed that nanocomposites were not cytotoxic against mouse embryonic fibroblast cell line, whereas they showed moderate cytotoxicity toward adenocarcinomic human epithelial cell line. Minor hemolytic effect of these nanocomposites toward red blood cells was revealed.

The synthesis of hybrid silver/zinc oxide (Ag/ZnO) decoration on the cellulose surface is described. The structures were characterized with X-ray photoelectron spectroscopy (XPS) and corroborated with X-ray diffraction and scanning electron microscopy. Silver nitrate and zinc acetate dihydrate were used as soluble raw materials. Hexamethylenetetraamine was used as the precipitating and reducing agent. The surface of a-cellulose was always treated by hydrogen peroxide before synthesis with a relatively mild effect manifested in water contact angle measurement and XPS high-resolution spectra. The Ag/ZnO decoration system was identified as a true nanodispersed metal/semiconductor hybrid with a unique collective plasmonic structure observed on Ag 3d core lines for the first time. A series of experiments with a single precursor solution contributed to the characterization of the interaction of Ag ? and Zn 2? species with the surface and to the description of the reaction mechanism in the mixed precursor solution. In contrast to previous reports, a specific interaction between the cellulose substrate and Zn 2? was observed. No specific non-thermal effects of microwave heating were observed.

Scaffolds can be considered as one of the most promising treatments for bone tissue regeneration. Herein, blends of chitosan, poly(vinyl alcohol), and hydroxyapatite in different ratios were used to synthesize scaffolds via freeze-drying. Mechanical tests, FTIR, swelling and solubility degree, DSC, morphology, and cell viability were used as characterization techniques. Statistical significance of the experiments was determined using a two-way analysis of variance (ANOVA) with p < 0.05. Crosslinked and plasticized scaffolds absorbed five times more water than non-crosslinked and plasticized ones, which is an indicator of better hydrophilic features, as well as adequate resistance to water without detriment of the swelling potential. Indeed, the tested mechanical properties were notably higher for samples which were undergone to crosslinking and plasticized process. The presence of chitosan is determinant in pore formation and distribution which is an imperative for cell communication. Uniform pore size with diameters ranging from 142 to 519 µm were obtained, a range that has been described as optimal for bone tissue regeneration. Moreover, cytotoxicity was considered as negligible in the tested conditions, and viability indicates that the material might have potential as a bone regeneration system.