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This work describes impact of concentration of BiFeO3 submicrometric particles on piezoelectric performance and structural characteristics of 0–3 polymer composites with a polystyrene matrix. Bismuth ferrite particles are fabricated using reverse co‐precipitation method, followed by ultrasonic dispersion in a solvent to break up agglomerates formed during sintering, resulting in particles with a size of ≈200 nm. It is found that concentrations higher than 10 wt% BiFeO3 lead to a disturbance in natural organization of polystyrene. The hindered organization of side‐groups by submicrometric filler, occurring during solvent evaporation, strongly affects the mechanical properties of the finalcomposite, significantly increasing Young's modulus and tensile strength, but decreasing elongation. Such behavior is detected and described for the firsttime in literature. Piezoelectric examinations show that the thermal depolarization of nanogenerators has a different impact depending on the amountof piezoelectric phase. The study reveals that a voltage of over 4.8 V is generated when dynamic air pressure is applied at 11.54 bar for the composite containing only 2.5 wt% BiFeO3. For composites with 10% weight fraction or lower, decrease in generated voltage after thermal depolarization is about 24%, while for higher weight fractions (15 and 20 wt%) the decrease is around 35%. [ABSTRACT FROM AUTHOR]

Even though electrospinning is getting more and more attention, the preparation of 3D nanofibrous meshes is still a big challenge that limits the application of electrospun materials, especially in tissue engineering. To overcome this problem, several solutions are introduced but most of them focus on the postprocessing of the electrospun meshes. This paper presents a straightforward novel method that utilizes the joint effect of the addition of CaCl2 and the relative environmental humidity (RH), which can induce the random 3D formation of polysuccinimide (PSI) electrospun fibers with different such as wrinkled or ribbon‐like structures. Although the effect of humidity and inorganic salt additives on the micro and macrostructure of electrospun fibers is known, the connection between the two in this manner has never been presented. To investigate the effect, fibers with different PSI and CaCl2 concentrations at different humidity RH levels are prepared, and their microstructure is visualized with high‐resolution scanning electron microscopy (SEM). To reveal the nature of the interaction between the polymer and the CaCl2, Fourier‐transformed infrared (FTIR), X‐ray diffraction (XRD), and thermogravimetry (TGA) measurements are carried out and 3D nanofibrous structures are obtained. [ABSTRACT FROM AUTHOR]

To create materials that interact effectively with electromagnetic (EM) radiation, new nanosized substituted ferrites (NiZn)1−xMnxFe2O4 (x = 0, 0.5, and 1) anchored on the surface of multi-walled carbon nanotubes (CNTs) have been synthesized. The concentration of CNTs in the (NiZn)1−xMnxFe2O4/CNT system was from 0.05 to 0.07 vol. fractions. The dielectric and magnetic characteristics of both pristine (NiZn)1−xMnxFe2O4 ferrites and (NiZn)1−xMnxFe2O4/CNT composite systems were studied. The introduction of (NiZn)1−xMnxFe2O4/CNT composites into the amorphous epoxy matrix allows to tailor absorbing properties at the high-frequency by effectively shifting the maximum peak values of the absorption and reflection coefficient to a region of lower frequencies (20–30 GHz). The microwave adsorption properties of (NiZn)1−xMnxFe2O4/0.07CNT–ER (x = 0.5) systems showed that the maximum absorption bandwidth with reflection loss below −10 dB is about 11 GHz. [ABSTRACT FROM AUTHOR]

Growing demand for electric energy in newly developed electronic systems causes increasing interest in research on piezoelectric nanogenerators (PENGs). Design and fabrication of such devices is challenging, considering cost of materials used in their construction. This is the main reason why intensive research has begun on 0‐3 composites with piezoelectric properties. One of the most promising constituent materials for composites fabrication are polymers, due to their low cost and easy processing. Herein, we present fabricated wearable PENG with good impact and vibration energy conversion properties. Correlation between matrix stiffness and piezoelectric properties of 0‐3 type composite is proposed. It was found that composite with 10 wt.% of BiFeO3 particles exhibits power output density for vibrations, finger tapping, and air stream pressure P = 11.12 nW cm−3, P = 4.83 μW cm−3, and P = 769.2 μW cm−3, respectively. Decrease in stiffness of epoxy matrix results at least in two‐times lower power output density for this same PENG. The obtained results demonstrate that the fabricated BFO/epoxy composites show the wide applicability and potential to be integrated with other functional devices, for example, as a part of wearable devices in smart shoes. [ABSTRACT FROM AUTHOR]

The interest in combining chemosensitizers with cytostatics in cancer therapy is growing, which causes also a need to develop their delivery systems. Example of the combination with beneficial therapeutic effects is docetaxel (Dtx) and resveratrol (Res). Although poly(lactide)‐co‐poly(ethylene glycol) (PLA–PEG) micelles have been considered as one of the most promising platforms for drug delivery, their properties may depend on the stereoisomeric form of hydrophobic block. Therefore, the aim of this study was evaluation of the effect of PLA block on co‐encapsulation and release rate of Dtx and Res, which has not been studied so far. This article presents a comparison of single‐ (Dtx or Res) and dual‐drug (Dtx and Res) loaded micelles obtained from poly(l,l‐lactide)‐co‐poly(ethylene glycol) (PLLA‐PEG) and poly(d,l‐lactide)‐co‐poly(ethylene glycol) (PDLLA‐PEG). The analyzes of the micelles have been conducted including morphology, drug(s) encapsulation efficiency, intermolecular interactions, in vitro drug release, and cytotoxicity. Differences in drug loading ability and release profile have been observed between Res and Dtx but also depending on the polymer and number of drugs in micelles (single vs. dual loaded). The PLLA‐PEG micelles have a significantly higher Dtx encapsulation capacity than PDLLA‐PEG micelles. The highest cytotoxicity was shown for Dtx and Res dual‐loaded micelles, regardless of the polymer. The findings may be used for selection of PLA‐based drug delivery systems containing Dtx and Res. [ABSTRACT FROM AUTHOR]

Cermet coatings provide protection against an aggressive operating environment of machine and device elements, such as corrosion, wear or high-temperature conditions. Currently, WC-based cermet coatings are frequently used in different industry branches. In this work, conventional WC-based powders (WC-Co and WC-Co-Cr) were sprayed with high velocity oxy fuel (HVOF) onto AZ31 magnesium alloy with different spray distances (320 and 400 mm). The research aimed to investigate the effect of the spray distance on the microstructure of the coatings, phase composition and electrochemical corrosion resistance. Results revealed that a higher spray distance results in greater porosity, 1.9% and 2.3% for 320 mm and 2.8% and 3.1% for 400 mm in the case of WC-Co and WC-Co-Cr coatings, respectively. Also, an impact on coatings microhardness was observed, c.a. 1300 HV0.3 for shorter spray distances, whereas for longer ones it was less than 1100 HV0.3. The corrosion resistance estimated in potentiodynamic polarization measurements was the best for WC-Co-Cr coating deposited from the shorter spray distance, corrosion current density was equal to 2:9 μA·cm-2 and polarization resistance was equal to 8424 Ω·cm2. [ABSTRACT FROM AUTHOR]