Jakub Krzeminski, Bartosz Blicharz, Andrzej Skalski, Grzegorz Wroblewski, Małgorzata Jakubowska and Marcin Sloma
Despite almost limitless possibilities of rapid prototyping, the idea of 3D printed fully functional electronic device still has not been fulfilled – the missing point is a highly…
Abstract
Purpose
Despite almost limitless possibilities of rapid prototyping, the idea of 3D printed fully functional electronic device still has not been fulfilled – the missing point is a highly conductive material suitable for this technique. The purpose of this paper is to present the usage of the photonic curing process for sintering highly conductive paths printed on the polymer substrate.
Design/methodology/approach
This paper evaluates two photonic curing processes for the conductive network formulation during the additive manufacturing process. Along with the xenon flash sintering for aerosol jet-printed paths, this paper examines rapid infrared sintering for thick-film and direct write techniques.
Findings
This paper proves that the combination of fused deposition modeling, aerosol jet printing or paste deposition, along with photonic sintering, is suitable to obtain elements with low resistivity of 3,75·10−8 Ωm. Presented outcomes suggest the solution for fabrication of the structural electronics systems for daily-use applications.
Originality/value
The combination of fused deposition modelling (FDM) and aerosol jet printing or paste deposition used with photonic sintering process can fill the missing point for highly conductive materials for structural electronics.
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Keywords
Lucja Dybowska-Sarapuk, Daniel Janczak, Bartlomiej Podsiadly, Malgorzata Jakubowska and Marcin Sloma
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…
Abstract
Purpose
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.
Design/methodology/approach
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.
Findings
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.
Originality/value
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.
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Marcin Sloma, Daniel Janczak, Grzegorz Wroblewski, Anna Mlozniak and Malgorzata Jakubowska
New types of substrates were used for fabrication of printed electroluminescent structures. Polymer foils mainly used as substrates for such optoelectronic elements were replaced…
Abstract
Purpose
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.
Design/methodology/approach
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.
Findings
Main issue with new substrates is proper wetting with the use of screen-printing pastes, and much higher roughness especially for textiles.
Originality/value
Fully functional structures were obtained, but several disadvantages were observed that needs to be eliminated in further studies.
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Keywords
Grzegorz Wroblewski, Marcin Słoma, Daniel Janczak and Malgorzata Jakubowska
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…
Abstract
Purpose
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.
Design/methodology/approach
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.
Findings
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.
Originality/value
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.