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A comparison of electric and viscosity percolation threshold is crucial from the scientific and technical points of view to understand the features and capabilities of heterogeneous graphene composite materials and properly select the functional phase volume. Therefore, the purpose of this paper is to present the analysis of the electrical and rheological percolation thresholds in the polymer–graphene screen printing pastes and the analysis of the relation between these two parameters.

In the paper, the properties of polymer-based pastes with graphene nanoplatelets were tested: paste viscosity and printed layers conductivity. The tests of pastes with different filler content allowed to determine both the electrical and rheological percolation thresholds using power law, according to Kirkpatrick’s percolation model.

The electrical percolation threshold for graphene nanoplatelets (GNPs) in the composite was 0.74 Vol.% when the rheological percolation threshold is observed to be at 1.00 Vol.% of nanoplatelets. The percolation threshold values calculated using the Kirkpatrick’s percolation model were 0.87 and 0.5 Vol.% of GNPs in the paste for electrical and rheological percolation thresholds, respectively.

Recently, GNPs are becoming more popular as the material of the functional phase in screen printing heterophase materials, because of their unique mechanical and electrical properties. However, till date no research presented in the literature is related to the direct comparison of both the electrical and rheological percolation thresholds. Such analysis is important for the optimization of the printing process toward the highest quality of printed conductive paths, and finally the best electrical properties.

The purpose of this paper is to present the result of research on a new fabrication technology of printed circuits board and electronics modules. The new method is based on inkjet printing technique on flexible substrates using new generations of heterophase inks. New fabrications method was used to print microwave waveguides and signal splitters as new technology demonstrators.

A fully Inkjet printed filter was printed on a flexible, transparent Kapton foil using heterophase inks developed in Instytut Technologii Materiałów Elektronicznych (ITME) for the purpose of this research based on graphene and silver nanoparticles.

A microwave module was printed using two types of Inkjet printers – PixDro LP50 with KonicaMinolta 512 printhead – and developed in an Instytut Tele- i Radiotechniczny (ITR) laboratory printer using MicroDrop a 100-μm glass nozzle printhead. Fully printed microwave circuits were evaluated by their print quality and electrical properties.

Fully Inkjet printed microwave circuits using the heterophase graphene ink were evaluated by their print quality and electrical properties.

The purpose of this work is to investigate the influence of carbon nanotube additions to solder paste on the solder joints mechanical strength and their microstructure. In our investigation, the basic solder paste contains 85 wt.% of the commercial Sn96.5Ag3Cu0.5 powder (with the particle sizes in the range of 20‐38 μm) and 15 wt.% of the self‐prepared middle activated rosin flux. To this paste we added the 0.01, 0.05 and 0.1 wt.% of the self‐modified CNT by functionalized them by mineral acid and than esterificated by methanol (FCNT_Met) or polyethylene glycol 400 (FCNT_PG). After the pastes had stabilized, the reflow soldering process of “zero ohm” chip resistors on PCBs with Ni/Au and SAC (HASL) finishes was carried out and then shear strength of the solder joints was measured. The correlations between the mechanical strength of solder joins without and with the carbon nanotubes and their microstructure were analysed.

For shear strength measurement of solder joints, the printed circuit boards with Ni/Au and SAC (HASL) finishes was applied. The SAC solder paste with different carbon nanotubes and the basic SAC solder paste as reference were used for this experiment. The automatic SMT line was applied for the paste screen printing; “zero ohms” chip resistors: 0201, 0402, 0603 and 0805 were placing on PWBs and then reflowing according to appropriate time – temperature profile. The shear strength of the solder joints was measured. For the solder joints microstructure analysis, the standard metallographic procedures were applied. Changes in the microstructure, the thickness of the intermetallic compounds and their chemical compositions were observed by means of the SEM equipped with EDS.

As the authors expected, the SAC solder paste with the carbon nanotubes addition improve the solder joints shear strength of the chip resistors mounted on PCBs with Ni/Au and SAC (HASL) finishes. The carbon nanotubes addition positive effects on IMCs thickness because of blocking their excessive growth.

It is suggested that further studies are necessary for the confirmation of the practical application, especially of the reliability properties of the solder joints obtained using solder paste with chosen carbon nanotubes.

Taking into account the shear strength data, the best results of the “nano” SAC solder pastes were obtained for the lowest addition of the carbon nanotubes modified by esterification process, especially by the methanol compared to the polyethylene glycol 400.

The obtained results made it possible to draw conclusions regarding the correlation between the output of the mechanical results and the amount of the added carbon nanotubes, and also the microstructure and thickness of the IMCs of the “nano” solder joints. It can be useful from practical point of view.

The aims of this paper are to investigate the influence of direct current (DC) electric field on separation and orientation of carbon nanotubes (CNTs) in spray-coated layers and apply this method to the fabrication of elastic and transparent electrodes. The orientation of CNTs in the form of paths in the direction of electrical conduction should increase the electrode conductivity without decreasing its optical transmission.

Materials are deposited using vacuum-free, ultra-fine nozzle spray coating technique, easily applicable for large-scale production. After the deposition of carbon nanomaterials, nanoparticles are oriented in the electric field and initially cured with infrared halogen lamp to evaporate solvents and preserve orientation of the nanoparticles in the deposited layer. Afterwards, layers are cured in a chamber dryer to obtain desired properties. Nanoparticles orientation and carbon nanomaterials separation via DC electric field are analysed, and the optical and electrical properties of prepared electrodes are measured.

Experiments described in this paper showed that DC electric field can be applied provide separation and orientation of CNTs and combined with spray coating technique, can be used as additional tool for tuning the conductivity of flexible and transparent electrodes by decreasing the sheet resistance about five times.

The results showed that spray coating combined with electric field orientation is a promising solution of obtaining elastic and transparent electrodes with oriented carbon particles. According to the authors’ knowledge, none of the experiments was directed to obtain DC electric field-oriented transparent layers produced with the use of spray coating technique.

The paper aims to present the research results related to transparent heating elements made from carbon nanomaterials. Heating elements were fabricated only with cost-effective techniques with the aim to be easily implemented in large area applications. Presented materials and methods are an interesting alternative to vacuum deposition of transparent resistive layers and etching of low-resistive patterns. Fabricated heating elements were designed to be used as de-icing structures in roof-top windows.

The paper presents the research results related to transparent heating elements made from carbon nanomaterials. Heating elements were fabricated only with cost-effective techniques with the aim to be easily implemented in large area applications. Presented materials and methods are an interesting alternative to vacuum deposition of transparent resistive layers and etching of low-resistive patterns. Fabricated heating elements were designed to be used as de-icing structures in roof-top windows.

The sheet resistance of obtained layers was between 9 and 11 kΩ/□; however, double-walled carbon nanotubes showed significantly higher optical transmission (around 70 per cent) than graphene nanoplatelets (around 55 per cent for visible and near infrared range). The amount of polymer resin had the influence on the paints stability, electrical properties and coatings adhesion.

Results show a novel method of fabrication of a large area and transparent heating elements with tunable resistance done through the change of spray coating paint composition.

New types of substrates were used for fabrication of printed electroluminescent structures. Polymer foils mainly used as substrates for such optoelectronic elements were replaced with paper and textiles. Printing on non-transparent substrate requires elaboration of printed transparent electrode, while usually polyester foils with sputtered ITO transparent electrodes are used. The paper aims to discuss these issues.

Electroluminescent structures were fabricated with elaborated polymer compositions filled with nanomaterials, such as carbon nanotubes and graphene platelets, dielectric and luminophore nanopowders. Structures were printed as “reverse stack”, where transparent electrode is printed on top of the last luminophore layer. For that carbon nanotubes and graphene platelets filled composition was used, deposited with spray-coating technique.

Main issue with new substrates is proper wetting with the use of screen-printing pastes, and much higher roughness especially for textiles.

Fully functional structures were obtained, but several disadvantages were observed that needs to be eliminated in further studies.