Nanocomposites based on waterborne polyurethane (WPU) and graphene oxide (GO) have been synthesized and characterized. It was found that after the incorporation of GO, WPU films became mechanically more rigid, and the Young’s modulus increased by almost six times. It is shown that the lateral size of GO sheets influences the mechanical properties of WPU/GO composites. In particular, composites with larger lateral size of GO sheets have higher values of Young’s modulus. Additionally, if the mechanical properties are improved with the addition of GO additive, then water absorption decreases for WPU modified with small GO sheets whereas it increases for WPU modified with large GO sheets. Possible reasons for this behavior are discussed.

Thermally stable films were obtained from a water-based polyurethane (PU) dispersion with small (0.1–1.5 wt.%) additions of graphene oxide (GO). The films were studied through elemental analysis, X-ray photoelectron spectroscopy, differential thermogravimetry, and Raman spectroscopy. It was found that the introduction of GO into a PU matrix was accompanied by a partial reduction in graphene oxide nanosheet and an increase in the concentration of defects in GO structure. It has been also established that the [C/N]_at ratio in the near-surface layer of PU/GO composite films grows with an increase in the content of graphene oxide in the composite films.

The composite of paraffin with reduced graphene oxide (paraffin/rGO) was obtained at 70 °C by the mechanical mixing of the components followed by ultrasonic dispersion. The introduction of only 0.3 wt.% rGO stained the paraffin black. It has been shown that thermal batteries made from 160 grams of pure paraffin and 160 grams of the composite are equally slow at charging when placed in boiling water. However, two minutes of microwave heating increases the temperature of the pure paraffin battery to only 32 °C, while the temperature of the paraffin/rGO composite battery rises to 74 °C, which is above the paraffin solid–liquid phase transition temperature.

Mechanically strong and thermally stable films obtained from a water-based polyurethane (PU) dispersion with small (0.1–1.5 wt.%) additions of graphene oxide nanosheet (GO) were studied through elemental analysis, X-ray photoelectron spectroscopy, differential thermogravimetry, and Raman spectroscopy. Moreover, the depletion of near-surface layers in nitrogen was presented for all the samples under study. It was found that the introduction of GO into a PU matrix was ac-companied by a partial reduction of graphene oxide nanosheet and an increase in the concentra-tion of defects in its structure.

A nanonet consisting of ultrathin Ni nanowires (diameter <4 nm) and Ni nanoballs (diameter <20 nm) has been grown through laser ablation of a Ni target in superfluid helium. At a low Ni concentration, the nanonet consists mainly of nanowires and manifests a rectangular magnetic hysteresis loop, while an increase in the Ni concentration results in an increase in both the concentration and diameter of the nanoballs. A decrease in hysteresis loop rectangularity is observed as the concentration of the nanoball increases. We show that the composition of the system can be determined from the changes in the magnetic hysteresis loop and the temperature dependence of magnetization. The significance of the work consists of the observation of evolution of magnetic properties of the ferromagnetic nanonet, while its composition varies from nanowires to a combined nanowires–nanoballs system.

Using selective dissolution, we create α-Fe/DyPrFeCoB microwires with a parabolic tip for focusing the magnetic flux and enhancing the magnetic attraction of particles. The conditions for sharpening the end of the microwire by etching with HNO₃ and with mixtures of HNO₃ + HCl and H₂SO₄ + HNO₃ are also optimized. The magnetic force of a single microwire with a pointed end (up to 880 pN) makes it possible to capture and hold a DyPrFeCoB microparticle with a size of 1 µm in the region of ~5 µm. A significant magnetic-field gradient (up to ~3.5 × 10⁵ T/m), created at the tip of the microwire, is sufficient to affect biological processes inside cells even without magnetic markers. The conditions for the attachment/detachment of a magnetic microparticle are controlled by the exchange bias arising at the interface between the α-Fe ferromagnetic core and the PrDyFeCoB ferrimagnetic shell and by four magnetic states of the microwire, which are switched by a weak external uniform magnetic field of ~0.1–2 kA/m.