scholarly journals Printed and Laser-Scribed Stretchable Conductors on Thin Elastomers for Soft and Wearable Electronics

2021 ◽  
Vol 8 ◽  
Author(s):  
Kirill Keller ◽  
David Grafinger ◽  
Francesco Greco
Keyword(s):  
Printed Electronics ◽  
Barrier Properties ◽  
Wearable Electronics ◽  
Electrical Measurements ◽  
Electromechanical Properties ◽  
Laser Scribing ◽  
Stretchable Conductors ◽  
Electromechanical Performance ◽  
Initial Resistance ◽  
Medical Grade

As printed electronics is evolving toward applications in biosensing and wearables, the need for novel routes to fabricate flat, lightweight, stretchable conductors is increasing in importance but still represents a challenge, limiting the actual adoption of ultrathin wearable devices in real scenarios. A suitable strategy for creating soft yet robust and stretchable interconnections in the aforementioned technological applications is to use print-related techniques to pattern conductors on top of elastomer substrates. In this study, some thin elastomeric sheets—two forms of medical grade thermoplastic polyurethanes and a medical grade silicone—are considered as suitable substrates. Their mechanical, surface, and moisture barrier properties—relevant for their application in soft and wearable electronics—are first investigated. Various approaches are tested to pattern conductors, based on screen printing of 1) conducting polymer [poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)] or 2) stretchable Ag ink and 3) laser scribing of laser-induced graphene (LIG). The electromechanical properties of these materials are investigated by means of tensile testing and concurrent electrical measurements up to a maximum strain of 100%. Performance of the different stretchable conductors is compared and rationalized, evidencing the differences in onset and propagation of failure. LIG conductors embedded into MPU have shown the best compromise in terms of electromechanical performance for the envisioned application. LIG/MPU showed full recovery of initial resistance after multiple stretching up to 30% strain and recovery of functionality even after 100% stretch. These have been then used in a proof-of-concept application as connectors for a wearable tattoo biosensor, providing a stable and lightweight connection for external wiring.

Repeatability and Extended Time Stability Study of an Additively Printed Strain Gauge Under Different Load Conditions

2021 ◽  
Author(s):  
Pradeep Lall ◽  
Jinesh Narangaparambil ◽  
Tony Thomas ◽  
Kyle Schulze
Keyword(s):  
Strain Gauge ◽  
Printed Electronics ◽  
Performance Testing ◽  
Temperature Limit ◽  
Stability Study ◽  
Strain Gauges ◽  
Gauge Factor ◽  
Wearable Electronics ◽  
Strain Sensing ◽  
Sintering Conditions

Abstract Printed electronics has found new applications in wearable electronics owing to the opportunities for integration, and the ability of sustaining folding, flexing and twisting. Continuous monitoring necessitates the production of sensors, which include temperature, humidity, sweat, and strain sensors. In this paper, a process study was performed on the FR4 board while taking into account multiple printing parameters for the direct-write system. The process parameters include ink pressure, print speed, and stand-off height, as well as their effect on the trace profile and print consistency using white light interferometry analysis. The printed traces have also been studied for different sintering conditions while keeping the FR4 board’s temperature limit in mind. The paper also discusses the effect of sintering conditions on mechanical and electrical properties, specifically shear load to failure and resistivity. The data from this was then used to print strain gauges and compared them to commercially available strain gauges. By reporting the gauge factor, the printed strain gauge has been standardized. The conductive ink’s strain sensing capabilities will be studied under tensile cyclic loading (3-point bending) at various strain rates and maximum strains. Long-term performance testing will be carried out using cyclic tensile loads.

scholarly journals Investigation of Carbon-Based Composites for Elastic Heaters and Effects of Hot Pressing in Thermal Transfer Process on Thermal and Electrical Properties

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7606
Author(s):  
Tomasz Raczyński ◽  
Daniel Janczak ◽  
Jerzy Szałapak ◽  
Piotr Walter ◽  
Małgorzata Jakubowska
Keyword(s):  
Flexible Electronics ◽  
Hot Pressing ◽  
Screen Printing ◽  
Printed Electronics ◽  
Wearable Electronics ◽  
Thermal Transfer ◽  
Wide Range ◽  
Thermal And Electrical Properties ◽  
Carbon Based ◽  
Screen Printed

Wearable electronics are new structures with a wide range of possible applications. This study aims to analyze the effects of hot pressing in thermal transfer of different carbon-based composites as a new application method of screen-printed electronics on textiles. Flexible heaters were screen-printed on polyethylene terephthalate PET foil with composites based on graphene, carbon black, and graphite with different wt.%, measured and then hot pressed to measure and analyze differences. Research showed that the hot pressing process in thermal transfer resulted in decreased electrical resistance, increased power, and higher maximal temperatures. Best results were achieved with composites based on 12 wt.% graphene with sheet resistance lowered by about 40% and increased power by about 110%. This study shows promise for thermal transfer and screen-printing combination as an alternative for creating flexible electronics on textiles.

Reinforcement of Cu nanoink sintered film with extended carbon nanofibers for large deformation of printed electronics

2016 ◽  
Vol 51 (7) ◽  
pp. 997-1003 ◽  
Author(s):  
Jeonghwan Kim ◽  
Akash Shankar ◽  
Jiahua Zhu ◽  
Daniel S Choi ◽  
Zhanhu Guo ◽  
...  
Keyword(s):  
Flexible Electronics ◽  
Printed Electronics ◽  
Carbon Nanofiber ◽  
Average Length ◽  
Scanning Electron Micrographs ◽  
Ambient Conditions ◽  
Metallic Nanoparticle ◽  
Electrical Measurements ◽  
Oxidized Carbon ◽  
Pure Cu

Metallic nanoparticle inks (nanoinks) have attracted great interest in the manufacturing of printed flexible electronics. However, sintering pure nanoinks in ambient conditions results in micro-cracks and pores within the sintered film, which deteriorate the mechanical and electrical characteristics of the sintered nanoinks. To alleviate these problems, we demonstrate the use of very long carbon nanofiber (average length 200 µm) to reinforce the sintered nanoink films. In this study, different weight fractions of carbon nanofiber are dispersed into the Cu nanoink to improve the mechanical bending characteristics. Scanning electron micrographs show improved dispersion of oxidized carbon nanofiber in the nanoink compared to the as-received carbon nanofiber. The composite nanoinks are stencil printed on polyethylene terephthalate film and sintered by intense pulsed light using Xe-flash. The electrical measurements show 90%, 65%, and 66% improved electrical conductivity in the composite nanoink film (0.7% of oxidized carbon nanofiber) compared to the pure Cu nanoink under the 7.5 cm, 5.0 cm, and 2.5 cm of bending radii, respectively.

scholarly journals Stretchable and Washable Electroluminescent Display Screen-Printed on Textile

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1276 ◽  
Author(s):  
Daniel Janczak ◽  
Marcin Zych ◽  
Tomasz Raczyński ◽  
Łucja Dybowska-Sarapuk ◽  
Andrzej Pepłowski ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Mechanical Strength ◽  
Rheological Properties ◽  
Polymer Composites ◽  
Screen Printing ◽  
Printed Electronics ◽  
Wearable Electronics ◽  
Printing Technology ◽  
Wide Range ◽  
Screen Printing Technology

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.

Integration of ALD-TaN Liners on Nanoporous Dielectrics

2005 ◽  
Vol 863 ◽  
Author(s):  
Bum Ki Moon ◽  
Tadashi Iijima ◽  
Sandra Malhotra ◽  
Andrew Simon ◽  
Thomas Shaw ◽  
...  
Keyword(s):  
Color Change ◽  
Average Pore Size ◽  
Barrier Properties ◽  
Optical Microscope ◽  
Deep Penetration ◽  
Electrical Measurements ◽  
Plasma Damage ◽  
Average Pore ◽  
K Value ◽  
Interlayer Dielectric

AbstractUltra-thin ALD-TaN/PVD-Ta liners have been developed to prevent Cu diffusion into porous interlayer dielectric (ILD) materials envisioned for future copper interconnections. The porous ultra-lowk(p-ULK) film is prepared using the spin-on method, and typical k-value and the average pore size of p-ULK used in this paper are 2.3 and 2-3 nm, respectively. Interaction and phenomena at the ILD/ALD-TaN interface have been investigated, and the electrical measurements of samples with a bi-layered ALD-TaN/PVD-Ta barrier were performed after completing the metallization and CMP process.A deep penetration of ALD-TaN was observed on the as-deposited p-ULK, which is due to the interconnected pore structures. However, the surface of the p-ULK is drastically changed after the etch process, where changes are attributed to plasma damage and re-deposition of etched species. Pores can therefore be sealed during the etch process. Furthermore, the plasma damage makes the sidewall more hydrophilic, which may promote the growth of ALD-TaN layer. Based on EELS and EDS profiles, there is no signature of TaN penetration into the etched p-ULK at M1 level with a sharp Ta peak, which indicates excellent stability of ultra-thin ALD-TaN liner.An oxidation test in air ambient and at elevated temperature confirmed the barrier properties of the stacked ALD-TaN/PVD-Ta layers. Any weak point in the barrier allows the Cu to oxidize and to make a color change under an optical microscope. However, all of our samples showed no color change, which implies that the barrier is very uniform and stable. Electrical properties measured at M1 showed excellent results. Our results demonstrate the ability to successfully integrate ALD-TaN barriers with a nanoporous ULK film.

Control of hard block segments of methacrylate-based triblock copolymers for enhanced electromechanical performance

2016 ◽  
Vol 7 (48) ◽  
pp. 7391-7399 ◽  
Author(s):  
Kie Yong Cho ◽  
Ara Cho ◽  
Hyun-Ji Kim ◽  
Sang-Hee Park ◽  
Chong Min Koo ◽  
...  
Keyword(s):  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Electric Fields ◽  
Triblock Copolymers ◽  
Atom Transfer ◽  
Electromechanical Properties ◽  
Electromechanical Performance ◽  
Hard Block

A series of well-defined hard–soft–hard triblock copolymers with various hard block segments were synthesized by Ru-based atom transfer radical polymerization (ATRP) (MWD < 1.26) in order to examine their electromechanical properties under electric fields.

scholarly journals Ferroelectric Domain Studies of KNN Single Crystals by Piezo-force and Transmission Electron Microscopy

2012 ◽  
Vol 18 (S5) ◽  
pp. 113-114
Author(s):  
Muhammad Asif Rafiq ◽  
Maria Elisabete Costa ◽  
Paula Maria Vilarinho ◽  
Ian M Reaney
Keyword(s):  
Single Crystals ◽  
Piezoelectric Materials ◽  
Lead Free ◽  
Local Domain ◽  
Electromechanical Properties ◽  
As Doping ◽  
Transmission Electron ◽  
Alternative Materials ◽  
Electromechanical Performance ◽  
Monolithic Ceramics

Piezoelectric materials find important applications in micro- and nano-electromechanical systems (MEMS/NEMS). Pb(Zrx,Ti1-x)O3 (PZT) is currently the most widely used composition for such applications but due to environmental concerns over the toxicity of lead, lead free alternative materials are required. K0.5Na0.5NbO3 (KNN) is considered as a potential lead free piezoelectric but the current generation of monolithic ceramics has inferior electromechanical properties as compared to PZT. Consequently, there is great interest in improving the piezoelectric properties of KNN ceramics and various methods such as doping, hot-pressing and texturing are currently being studied. KNN single crystals like lead based single crystals have shown better electromechanical properties as compared to their ceramic counterparts. In addition, the behavior of a ferroelectric is largely dependent on its local domain response to an applied electrical or mechanical loading. Therefore, to understand better the material’s macroscopic properties, it is essential to access local ferroelectric domains behavior which collectively determines the electromechanical performance.

scholarly journals A Laser Scribed Graphene Oxide and Polyimide Hybrid Strain Sensor

2018 ◽  
Vol 778 ◽  
pp. 169-174 ◽  
Author(s):  
Shayan Naveed ◽  
Tayyaba Malik ◽  
Muhammad Muneer ◽  
Mohammad Ali Mohammad
Keyword(s):  
Graphene Oxide ◽  
Printed Electronics ◽  
Testing Machine ◽  
Strain Sensor ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Hybrid Strain ◽  
Laser Scribing ◽  
Prosthetic Limbs ◽  
Strain Testing

Strain sensors are devices used in applications such as electronic skin, prosthetic limbs, and e-textile applications, etc., for the purpose of measuring the physical elongation of a desired structure under a given or applied force. An artificial throat, using a strain sensor, was recently developed as an aid for speech impaired individuals. Strain sensors have been developed using graphene and polydimethylsiloxane (PDMS), with a reported gauge factor ranging from (5~120). We have developed a strain sensor through laser scribing. Using laser scribing is a recent and facile technology, used for printed electronics. Complex geometries and patterns can be drawn very easily using this method. The laser scribing method relies on the property of certain materials to form a graphene-like conductive material upon irradiation by lasers. Polyimide and graphene oxide (GO) are two such materials.In these experiments, 2×2 cm sheet of polyimide were taken and printed 1×1 cm box on the sheet using a laser patterning setup of 450 nm wavelength. Graphene oxide solution was drop-casted on the reduced polyimide sheet of 1×1cm, to increase its sensitivity, and then the drop-casted graphene oxide was reduced using the same laser. The strain sensor was characterized by a micro-strain testing machine. The normalized resistance was plotted against strain and the gauge factor was calculated. The effect of the laser intensity was investigated and different gauge factors were calculated by varying the intensity of the laser. The gauge factors were found to be in the range of 49-54 and was compared with the polyimide reduced strain sensor (without drop-casting the GO).

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