Stretchable polymer composites are a new group of materials with a wide range of application possibilities in wearable electronics. The purpose of this study was to fabricate stretchable electroluminescent (EL) structures using developed polymer compositions, based on multiple different nanomaterials: luminophore nanopowders, dielectric, carbon nanotubes, and conductive platelets. The multi-layered EL structures have been printed directly on textiles using screen printing technology. During research, the appropriate rheological properties of the developed composite pastes, and their suitability for printed electronics, have been confirmed. The structure that has been created from the developed materials has been tested in terms of its mechanical strength and resistance to washing or ironing.

Inkjet printing is an excellent printing technique and an attractive alternative to conventional technologies for the production of flexible, low-cost microelectronic devices. Among many parameters that have a significant impact on the correctness of the printing process, the most important is ink viscosity. During the printing process, the ink is influenced by different strains and forces, which significantly change the printing results. The authors present a model and calculations referring to the shear rate of ink in an inkjet printer nozzle. Supporting experiments were conducted, proving the model assumptions for two different ink formulations: initial ink and with the addition of a dispersing agent. The most important findings are summarized by the process window regime of parameters, which is much broader for the inks with a dispersing agent. Such inks exhibit preferable viscosity, better print-ability, and higher path quality with lower resistivity. Presented results allow stating that proper, stable graphene inks adjusted for inkjet technique rheology must contain modifiers such as dispersing agents to be effectively printed.

Biofilms are microbial communities of surface-attached cells embedded in a self-produced extracellular matrix. They have been found to play a role in a wide variety of infections, including catheter-related urinary tract and bloodstream infections, and, therefore remain a significant source of morbidity and mortality among the world's population. Recently, much attention has been devoted to the prevention of biofilm formation on implant surfaces. Nanomaterials such as graphene, characterized by antibacterial activity and low toxicity to human cells, are promising candidates for biomedical applications. This study investigates the antibacterial efficiency of graphene and specially produced graphene decorated with silver nanoparticles, obtained by one of the methods of printed electronics (spray-coating system). These methods are not only economical, but also enable the printing of layers of various thicknesses on different types of materials, including flexible and nonplanar substrates. The aim of the study was to reveal the ability of graphene and graphene-nanosilver layers to prevent the formation of Staphylococcus epidermidis biofilm on the surface of a Foley catheter.

Composite transparent electrodes based on carbon nanostructures such as multiwalled carbon nanotubes and graphene platelets were spray coated onto glass substrates and characterized by spectrophotometry and spectroscopic ellipsometry measurements. The dispersion relations of the ellipsometric angle rate, i.e. W and D versus wavelength k were measured in spectral range from 190 to 1700 nm. On the basis of these results, it was possible to estimate the value of the refractive index and extinction coefficient. Effective medium approximation model was chosen to calculate the optical constants of a mixed material. The average surface roughness and the average thickness of spray coated transparent resistive layers were also determined. The materials have a heterogeneous structure as confirmed by scanning electron microscopy and optical measurements (changes of depolarisation). From the Tauc plot it was possible to determine the energy gap. The influence of the coating process and the paint preparation on the optical properties was observed.

Flexible and transparent electrodes were fabricated with spray coating technique from paints based on multiwalled carbon nanotubes with the addition of graphene platelets. The work presents the influence of graphene platelets on the paints rheology and layers morphology, which has a strong connection to the electrooptical parameters of the electrodes. The paints rheology affects the atomization during spray coating and later the leveling of the coating on the substrate. Both technological aspects shape the morphology of the electrode and the distribution of nanoparticles in the coating. All these factors influence the sheet resistance and roughness, which is linked to the optical transmission and absorbance. In our research the electrode was applied as a transparent and elastic heating element with 68% optical transmission at 550 nm wavelength and 8.4 kΩ/□ sheet resistance. The elastic heating element was tested with a thermal camera at the 3 diverse supply voltages −20, 30, and 60 VDC. The test successfully confirmed and supported our proposed uses of elaborated electrodes.

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Nerve regeneration through cell electrostimulation will become a key finding in regenerative medicine. The procedure will provide a wide range of applications, especially in body reconstruction, artificial organs or nerve prostheses. Other than in the case of the conventional polystyrene substrates, the application of the current flow in the cell substrate stimulates the cell growth and mobility, supports the synaptogenesis, and increases the average length of neuron nerve fibres. The indirect electrical cell stimulation requires a non-toxic, highly electrically conductive substrate material enabling a precise and effective cell electrostimulation. The process can be successfully performed with the use of the graphene nanoplatelets (GNPs)—the structures of high conductivity and biocompatible with mammalian NE-4C neural stem cells used in the study. One of the complications with the production of inks using GNPs is their agglomeration, which significantly hampers the quality of the produced coatings. Therefore, the selection of the proper amount of the surfactant is paramount to achieve a high-quality substrate. The article presents the results of the research into the material manufacturing used in the cell electrostimulation. The outcomes allow for the establishment of the proper amount of the surfactant to achieve both high conductivity and quality of the coating, which could be used not only in electronics, but also—due to its biocompatibility—fruitfully applied to the cell electrostimulation.

The aim of the study was to produce heterophasic graphene nanoplatelets based formulation designed for ink-jet printing and biomedical applications. The compositions should meet two conditions: should be cytocompatible and have the rheological properties that allow to apply it with ink-jet printing technique. In view of the above conditions, the selection of suspensions components, such as binder, solvent and surfactants was performed. In the fi rst stage of the research the homogeneity of the dispersion of nanoplatelets and their sedimentation behaviour in diverse solutions were tested. Subsequently, the cytotoxicity of each ink on human mesenchymal stem cells was examined using the Alamar Blue Test. At the same time the rheology of the resulting suspensions was tested. As a result of these tests the best ink composition was elaborated: water, polyethylene glycol, graphene nanoplatelets and the surfactant from DuPont company.