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The possibility of printing conductive ink on textiles is progressively researched due to its potential benefits in manufacturing functional wearable electronics and improving wearing comfort. However, few studies have reported the effect of conductive ink formulation on electrodes directly screen-printed on flexible substrates, especially printing UV curable conductive ink on common textiles. In this work, a novel UV curable nano-silver ink with short-time curing and low temperature features was developed to manufacture the fully flexible and washable textile-based electrodes by screen printing. The aim of this study was to determine the influence of ink formulation on UV-curing speed, degree of conversion, morphology and electrical properties of printed electrodes. Besides, the application demonstration was highlighted. The curing speed and adhesion of ink was found depending dominantly on the type of prepolymer and the functionality of monomer, and the type of photoinitiator had a decisive effect on the curing speed, degree of double bond conversion and morphology of printed patterns. The nano-silver content is key to guarantee the suitable screen-printability of conductive ink and therefore the uniformity and high conductivity of textile-based electrodes. Optimally, an ink formulation with 60 wt% nano-silver meets the potential application requirements. The electrode with 1.0 mm width showed significantly high electrical conductivity of 2.47 × 106 S/m, outstanding mechanical durability and satisfactory washability. The high-performance of electrodes screen-printed on different fabrics proved the feasibility and utility of UV curable nano-silver ink. In addition, the application potential of the conductive ink in fabricating electronic textiles (e-textiles) was confirmed by using the textile-based electrodes as the cathodes of silver-zinc batteries. We anticipate the developed UV curable conductive ink for screen-printing on textiles can provide a novel design opportunity for flexible and wearable e-textile applications.

Printing techniques have been extensively studied as a promising route towards large-scale, low-cost and high-throughput manufacturing process for electronic devices. With the recently emerging applications in wearable electronics and customizable conformal electronics, it calls for the necessity to develop printed electronics that function on complex, 3D nonplanar architectures. In this study, aerosol printing and flash sintering of conformal conductors on nonplanar surfaces are demonstrated. Various printed patterns are fabricated by aerosol printing of conductive ink by copper nanoparticles (Cu NPs) on both planar and nonplanar surfaces. Pulsed flash light introduces rapid sintering of the printed Cu patterns in the ambient environment. For the nonplanar patterns, a back reflector is utilized to improve the uniformity of sintering. As a result, highly conductive customizable nonplanar Cu patterns with conductivity at 10%–12% of that of bulk Cu are obtained. Effects of different sintering conditions, including sintering voltage and mounting distance on the conductivity of sintered patterns are studied. For nonplanar patterns, conductivity values at different localized spots on the nonplanar rod are also investigated to evaluate the uniformity of nonplanar sintering. The processes of aerosol printing and flash sintering have provided a facile manufacturing route for conformal conductors on arbitrary nonplanar objects.

Background Inkjet printing of graphene conductive inks plays a critical role in the technological advancement in flexible and stretchable electronics applications. In this study, water-based graphene conductive ink was fabricated and printed through inkjet printing on polyethylene terephthalate substrate. Methods Deionized (DI) water and three different types of surfactants (sodium dodecyl sulfate (SDS), polyvinylpyrrolidone (PVP), and Gum Arabic GA)) were utilized in the preparation of graphene conductive inks. Significant Finding Among other conductive ink formulations, graphene conductive inks fabricated using the DI/PVP surfactant exhibit relatively higher wetting and stability properties. In addition, this formulation led to an increment of about 80% in electrical conductivity compared to DI water-based conductive ink. The results revealed an improvement of about 50 times in the electrical conductivity of the printed film when the number of the printing cycle was increased from 1 to 10. Furthermore, it was observed that under 50% tensile strain, the graphene film prepared using the PVP surfactant exhibited only a 0.12% drop in electrical conductivity. Therefore, it is inferred that the conductive inks prepared from DI/PVP surfactants are highly suitable for use in flexible and wearable electronics.

As a critical component for the realization of flexible electronics, multifunctional electronic textiles (e-textiles) still struggle to achieve controllable printing accuracy, excellent flexibility, decent washability and simple manufacturing. The printing process of conductive ink plays an important role in manufacturing e-textiles and meanwhile is also the main source of printing defects. In this work, we report the preparation of fully flexible and washable textile-based conductive circuits with screen-printing method based on novel-developed UV-curing conductive ink that contains low temperature and fast cure features. This work systematically investigated the correlation between ink formulation, rheological properties, screen printability on fabric substrates, and the electrical properties of the e-textile made thereafter. The rheological behaviors, including the thixotropic behavior and oscillatory stress sweep of the conductive inks was found depending heavily on the polymer to diluent ratio in the formulation. Subsequently, the rheological response of the inks during screen printing showed determining influence to their printability on textile, that the proper control of ink base viscosity, recovery time and storage/ loss modulus is key to ensure the uniformity of printed conductive lines and therefore the electrical conductivity of fabricated e-textiles. A formulation with 24 wt% polymer and 10.8 wt% diluent meets all these stringent requirements. The conductive lines with 1.0 mm width showed exceptionally low resistivity of 2.06 × 10−5 Ω cm Moreover, the conductive lines presented excellent bending tolerance, and there was no significant change in the sample electrical resistance during 10 cycles of washing and drying processes. It is believed that these novel findings and the promising results of the prepared product will provide the basic guideline to the ink formulation design and applications for screen-printing electronics textiles.

Recently, a novel mechanical energy harvesting method named triboelectric nanogenerator (TENG) is reported, and it has aroused great repercussions in the academic fields. But, the complex preparation process still limits its wide application. In this paper, the cotton film was used as the triboelectric material to fabricate a novel wearable TENG (W-TENG). The polytetrafluoroethylene (PTFE) film and cotton film play the role of triboelectric pair. The W-TENG can be used to harvest low-frequency mechanical energy in our environment, especially for human body mechanical energy, and then convert them to electrical energy. In addition, the cotton coated with conductive ink plays the role of conductive material for TENG. The Voc and Isc of W-TENG can reach 556 V and 26 μA, respectively. As for the maximum power density of W-TENG, it can arrive at 0.66 mW/cm2. Also, a combined W-TENG was proposed to improve the electrical output. Moreover, the W-TENG can play the role of human motion sensor for human walking posture monitoring. This will open up a new path for the preparation of high output TENG at low cost, and promote the TENG devices in the field of sports monitoring.

A sonication of graphite in polysaccharide (pullulan, chitosan and alginate) is one of the viable methods for the preparation of few-layer graphene. However, the effect of these adsorbed polysaccharides on the electrical performance of the produced graphene so far is not yet clear. In order to investigate the present effect of pullulan, chitosan and alginate on the electrical characteristic of resulted graphene, we have produced few-layer graphene using bath sonication of graphite in pullulan, chitosan and alginate medium for the application as electrical conductive ink in strain-sensitive. Data from the TEM reveals the appearance of folded few-layer graphene flakes after sonication for 150 min while the XPS data shows that the chitosan-based graphene possesses the highest carbon-oxygen ratio of 7.2 as compared to that of the pullulan and alginate-based graphene. By subjecting the produced graphene as the ink for paper-based strain sensor, we have discovered that the chitosan-graphene has the best resistivity value (1.66 × 10-3 Ω⋅cm) and demonstrate the highest sensitivity towards strain (GF: 18.6). This result interestingly implies the potential of the reported chitosan-based conductive ink as a strain-sensitive material for future food packaging.

The synthesis of few-layer graphene from graphite typically uses N, N methyl pyrrolidone (NMP) or dimethylformamide (DMF) due to the strong affinity of both solvents for graphite. However, NMP and DMF are known as carcinogens and a long-time exposure to these substances may subject users to potential risk of major health issue later. Therefore, a replacement with dispersing solvent that is not only harmless but also able to exfoliate graphite at an excellent concentration yield must be outlined for a sustainable mass-production of graphene. In this work, we have successfully exfoliated graphite to few-layer graphene with a recorded yield concentration of up to 0.75°mg/ml (2.5°h) just by using extracted red spinach/water mixture as an exfoliating medium. The prepared graphene was found to possess less structural defect (ID/IG: 0.5) and high C/O ratio (6.8) and can be used further as an electrical conductive ink for smart “Sticky Note” sensor. The fabricated device was able to detect strain and temperature with gauge factor and temperature coefficient resistance of 23.5 and −32.14 × 10-4°Ω/°;C, respectively. We believe that this study would be useful for the preparation of environmental-friendly graphene that is not only strain and thermally sensitive but also producible at low -cost.

Cellulose nanofibers (CNF) are promising nanomaterials for functional inks and printed sensors, although the potential applications are currently limited by the available functionalization methods. This work outlines a convenient method to grow a novel and highly conductive network of single-crystalline gold nanowires (AuNW) on CNF for use in conductive inks and printed sensors. The CNF are able to reduce Au (III) precursors to Au (0) monomers and generate nucleation sites for the subsequent monomer-by-monomer growth of Au nanocrystals; sodium citrate is used to control the reduction kinetics and the crystal growth. The growth of these AuNW/CNF materials is a three-step process of redox reaction, isotropic nucleation and anisotropic crystallization: the morphology and crystal structure of Au nanocrystals on CNF can be controlled by adjusting the reaction temperature and concentrations of citrate and CNF. The AuNW/CNF materials obtained have been formulated into highly conductive and atmospherically stable inks for use in either directly writing or screen printing. We have demonstrated AuNW/CNF-printed sensors with highly controllable electrical conductivity as well as excellent stability against rinsing and immersion by water and ethanol.

Copper conductive ink has great potential as an electrode material for flexible electronics due to its low-cost relative to silver conductive ink while having comparable electrical conductivity. The process of fabricating anti-oxidation hybrid copper conductive ink, however, results in an increase of required sintering energy; a high sintering temperature is disadvantageous due to the possibility of thermally damaging the substrate. In this study, selective laser sintering of new hybrid ink compositions was investigated by varying laser intensities and comparatively analyzing the resulting electrical conductivity. Then, the thermal behavior of fabricated inks during the sintering process was studied using experimental and numerical approaches. A finite element model was developed to simulate the laser heat flux and irradiation paths on the ink. Finally, the obtained results of the thermal profile were verified experimentally.

Paper-based devices are always more gaining a relevant position in the field of sensors. The continuous demand for affordable, simple, sustainable, and portable devices, is making paper as the ideal basis towards the realization of analytical tools for the easy self-testing. In this work, we demonstrate, for the first time, the development of a disposable paper-based printed electroanalytical strip for reliable, rapid, and high-throughput detection of glutathione in blood. The detection is based on the thiol-disulfide exchange reaction, which produces a detectable compound easily oxidizable at a Prussian Blue/carbon black nanocomposite involving a favorable low-interference overpotential. This nanocomposite is mixed within a carbon-based conductive ink and successively screen-printed onto a wax-patterned filter paper. The employment of paper provides a reagent-free device, as a consequence of the reagents pre-loading within the testing area. After the experimental conditions have been optimized, glutathione has been detected up to 10 mM, with a detection limit of 60 μM, and a sensitivity of (0.102 ± 0.005) μA/mM. This sensor showed satisfactory repeatability (relative standard deviation equal to 10%, for detection of glutathione 1 mM), especially by considering the hand-made manufacturing process. The “real-world” applicability of this strip has been evaluated by quantifying blood glutathione at physiological levels and by recovery studies achieving satisfactory values.

Bimetallic Cu-Ag Core-shell nanoparticles were synthesized by the reduction of copper 2-[2-(2-methoxyethoxy)ethoxy]acetate with hydrazine hydrate in benzyl alcohol followed by the reduction of silver ions on the copper surface using a galvanic replacement reaction. The morphology and Core-shell structure of the nanoparticles so prepared were investigated by X-ray phase analysis, high-resolution transmission electron microscopy, X-ray energy dispersive spectrometry and optical spectroscopy. The effect of synthesis conditions such as temperature, synthesis time, silver-to-copper molar ratio, and the rate of addition of silver nitrate to the system on thickness, density, and uniformity of the silver shell was studied. The silver coated copper nanoparticles were shown to exhibit improved stability to oxidation.

Graphene-based conductive ink has been widely applied to printed electronics, which nevertheless faces several challenges, e.g., dispersion and stability of graphene flakes and ideal compromise between conductivity and transparency. This work reveals a multi-component synergistic stabilization method towards a well-dispersed and stable graphene-based conductive ink with high conductivity and transparency. Commercially available graphene (

Microbial fuel cell (MFC) technology has been widely experimented nowadays, as it is a promising clean energy technology, which can harvest bioelectricity while simultaneously treating wastewater. Platinum (Pt), a precious transition metal, has long been regarded as a superior catalyst material for oxygen reduction reaction (ORR) at the cathode of the MFCs, however the high cost associated with it clutch it back for field scale applications. In this study, Co3O4 or Fe3O4 was blended with synthetically prepared conductive ink to act as microporous layer to explore its efficacy as an ORR catalyst. Applicability of these catalysts on cathode was investigated in dual chambered aqueous cathode MFCs and the performance was compared with MFC without any cathode catalyst, MFC with only conductive ink and another MFC with Pt as benchmark ORR catalyst. X-Ray diffraction, Fourier transform infrared spectra, Raman and field emission scanning electron microscope analysis were done to characterize the prepared catalysts. Cathode containing Co3O4 with conductive ink demonstrated higher reduction current (- 30 mA) than cathode having Pt and conductive ink with Fe3O4 (- 9 mA each) during cyclic voltammetry analysis. MFCs having cathodes printed with conductive ink containing Co3O4 and Fe3O4 exhibited a maximum volumetric power density of 6.62 W m−3 and 5.06 W m−3, respectively, which were much higher than the one without any catalyst (2.95 W m−3). Similarly, coulombic efficiency (CE) of 22.3%, 17.1% and 11.2% was observed in MFCs having cathode with conductive ink containing Co3O4 or Fe3O4 and without any catalysts, respectively. Moreover, more than 90% chemical oxygen demand removal efficiency was observed for MFCs having cathode with conductive ink containing Co3O4 or Fe3O4. Importantly, the performance obtained from MFC with conductive ink blended Co3O4 was found superior compared to MFC having Pt as cathode catalyst, where later produced power density of 6.13 W m−3 and CE of 21.1%. Hence, it can be concluded that Co3O4 can be used as an alternative to expensive platinum for efficient ORR in MFCs to make this technology effective for field scale application.

Stability of conductive ink and mechanical flexibility of conductive pattern are essential for flexible printed electronics. In this work, we reported a stable reactive silver ink for the facile fabrication of flexible electrodes. The ink was mainly composed of silver-isopropanolamine (IPA) complex, formic acid reductant, and hydroxyethyl cellulose (HEC) adhesive agent, and it displayed good chemical stability. The flexible electrodes on polyimide (PI) substrates were achieved by mask-printing and thermal sintering of the ink, and the effects of sintering parameters and HEC adhesive agent content on the electrical and flexible properties and microstructure evolutions of silver layer were systematically investigated. Consequently, the silver layer sintered at 110 °C yields low electrical resistivity of 12.1 μΩ·cm, which is only eight times higher than that of bulk silver. Furthermore, the sintered silver layer still presents excellent flexibility and low relative resistances after the bending, twisting, and folding tests. These results demonstrate that the stable reactive silver ink provides a promising and low cost opportunity for low temperature design and fabrication of high performance flexible printed electronics.

An enzyme conductive ink was synthesized and applied for the sensitive detection of l -proline in human biofluids. The nano-ink is a mixture of materials graphite (Gr), intermediates Methylene blue (MB), binding agents (Polyethylene glycol and chitosan), and Proline dehydrogenase (PRODH). The morphology of enzymatic ink composition was evaluated by using high-resolution field emission scanning electron microscope (FE-SEM). The results showed that the particle size of the proposed ink was below 100 nm. For electrochemical testing, the ink was fixed on the surface of copper electrode through utilization drop-casting technique via strong bonding between PEG and surface. The modified electrode was used as an electrochemical biosensor for the determination of l -proline in the alkaline solution. In optimal conditions, the concentration range and low limit of quantification (LLOQ) were 56 μM–1 mM and 56 μM, respectively.

The article presents end evaluates foil transducers, namely conductive rubber and conductive ink, and their use in the pressure distribution measurement system Plantograf. The ability of both materials to act as transducer between pressure and electrical quantities is assessed by means of measurement on a robotized workspace; two electrode types and various ink layer thicknesses are studied. Basing on the measurements, we present graphically the dependency of the electrical resistance of the materials on the applied pressure. Although both materials proved their ability to act as a transducer in a planar sensor, they both exhibit some limitations. In case of rubber it is limited pressure range up to ca. 1 400 kPa and significant hysteresis of the material. The main limiting factor with conductive ink is its poor adherence to the electrodes, which poses important problem for its practical use, although this material evinces better transfer characteristics, particularly in the configuration with 7 μm ink layer and LD type electrode.

In this paper, an intensive study is proposed to recycle the organic materials use for microwave applications including RF-energy harvesting. Thus, the Iraqi Palme Tree Remnants (IPTR) is exemplified for this study to create dielectric substrates. The main texture of the fabricated substrates is IPTR mixed with Nickel Oxide Nanoparticles (NONP) hosted in Polyethylene (PE) to be called INP substrates. Nevertheless, a metamaterial (MTM) printed antenna on the proposed substrate is fabricated by material printer with Sliver Nanoparticles Conductive Ink (SNPCI). The antenna performance is tested numerically/experimentally in terms of S11 spectrum and radiation patterns. It is found excellent matching bandwidths at 2.45 GHz and 5.8 GHz frequencies with acceptable gains of 1.56 dBi and 2.48 dBi, respectively. The proposed antenna bandwidth is found to start from 2.4 GHz up to more than 10 GHz. The maximum achieved gain and efficiency are found about 3.456 dBi and 78% at 9 GHz. For this, the proposed antenna provides novel performance with ultimate antenna size reduction due to the introduction of the MTM based the proposed INP substrate. Finally, the harvested RF energy by the fabricated antenna is measured and found about 15 mV with a conversation efficiency of 85% at 2.45 GHz and 17.5 mV with a conversion efficiency of 91% at 5.8 GHz.

Wearable strain sensors for various applications, such as human motion detection, soft robotics, and healthcare have recently received extensive attention. Although a number of strain sensors based on various active materials have been proposed, a simple and practical method to obtain both high stretchable and sensitive strain sensors remains challenging. This paper presents a simple, scalable and environment-friendly fabrication method for wearable strain sensors, based on wool yarns, as abundant, lightweight, and stretchable natural materials. A simple coating technique was used to achieve highly conductive wool yarns using a conductive ink. Different types of strain sensors were then fabricated by changing the shape of the active material within the elastomer to tune their sensitivity. In detail, the conductive yarns were sandwiched within the Ecoflex in the form of a straight line (CWY-1 strain sensors) or serpenoid curves (CWY-2 and CWY-3 strain sensors). The strain sensors were fully characterized up to 200% of applied tensile strain. Gauge factors of 5 and 7.75 were found within the percentage stretch ranges of 0–127 and 127–200 %, respectively, for the CWY-1 strain sensors. We have also demonstrated the ability of the strain sensors to monitor human muscle and joints movements.

Smart wearable textile’ becomes a major segment of electronic-textiles (e-textiles) along with smart clothing and information science (wearable computer). Wearable textiles can sense, react and adapt themselves accordingly to external conditions or stimuli and wearable textiles can be divided into active and passive smart wearable textiles which can be work with human brain with cognition, reasoning, activating capacity. Generally, different unsaturated polymeric substrates as polyaniline, polypyrrole, polytiophene and polyacetylene are used as inherently conductive materials. Now these day single/ multiwalled-nano carbon tubes (SWCNT/MWCNT) and Ag, Cu, Au nanoparticles are used as e-textiles basic yarn materials with variable cross sectional areas (sandwiched, coated, shelled, tri-lobal or twisted forms). Their conductivity ranges can varies within 10-1-10-8-cm-1. The products are assorted with a varieties of depth as centrally controlled sensors, actuators, circuit tree added conductive stitched or embroidered fabric, planer electric yarn, data transferring devices, conductive ink printing, textile Bluetooth antenna, integrated fabric area networked clothing, EMI shielding, power supply clothing, Numetrex sports bra (Textronics), intelligence textile wears like WarmX vest, textile headband for facial EMG and knee sleeve and flex sensor or even as pressure sensor providing relief from post-medical operational health risk hazards. e-textiles can be used in military applications in detection of enemies or biochemical threats. Recently developed ‘Biodegradable Smart Shirt’ textile platform is also able to monitor vital signs and heartbeats or palpitation rates for the patient using data management based information applications. Wearable e-textile has been introduced to fashion articles, for example: ICD+ Jacket with fabricated embroidered textile keypad or improvised to Softswitch remote control and light switch and pillow covers (made by Phillips Electronics and Levi Strauss) which can perform multiple modalities of works like mobile connect, geo-navigation and MP3 players as per the consumer’s choices. This paper particularly aims to review all the latest developments of wearable e-textiles.

Flexible hybrid electronic (FHE) material systems embody the intersection of compliant electrical networks and functional material architectures. For a wide variety of future applications, FHE material systems will be subjected to dynamic mechanical stresses, such as for motion monitoring or for vibration isolation . Consequently, an understanding is required on how these new classes of material systems may respond mechanically and electrically when under states of high-cycle and high-frequency loads. Here, conductive silver microflake ink is interfaced with elastomeric geometries programmed with specific strain responses. Changes in electrical resistance under cyclic displacements are shown to depend on the heat generated by electrical current flow and on the thermal heat generation promoted by the pre-strain on the material system. Configurations subject to high static pre-strains and large strain rates exhibit greater increases in temperature and resistance, whereas a near constant conductivity is manifest in FHE material systems with compositions that reduce static local strains despite high engineering pre-strain application. These results may guide future efforts to understand the resistance change in conductive ink networks and expand the use of flexible hybrid electronic material systems into myriad dynamic application environments.

Commercial diabetes test strips, patterned with a carbon paste, has poor durability and preservability because of using enzyme. Furthermore, carbon paste needs sintering process to get proper conductivity. Therefore, alternative conductive ink and sensing materials are the research theme under consideration lately. Therefore, we demonstrated constructing copper nanowire paste glucose sensor strip (CuNW_GSS) platform to diagnose diabetes nonenzymatically. Copper nanowires (CuNWs) were fabricated by a simple hydrothermal method with a capping agent to preserve the CuNWs from oxidation. Moreover, the CuNW paste could be easily utilized without sintering, and this fabricated paste successfully substituted for the commercial carbon paste pattern due to its high conductivity. CuNWs were used as not only the composition of conductive copper paste but also the sensing material for detecting glucose, which grants high charge transport ability to the glucose sensor, leading to high sensing ability. The limit of detection (LOD) of the CuNW_GSS was 1 nM, which is 40 times higher sensitivity than those of other glucose sensors and the CuNW_GSS also exhibited excellent selectivity. The excellent sensitivity and selectivity clearly indicate the great potential of the CuNW_GSS in diagnosing diabetes easily.

The silver nanoparticle (AgNP) ink synthesized was simple, well-dispersed, did not need sintering, had excellent conductivity and can be used as a conductive ink in several areas, particularly in the fabrication of reference electrodes. The AgNP ink was fabricated by synthesizing AgNP using the polyol method and then dispersing in methanol to fabricate the conductive ink. The synthesis was explained step-by-step, the proposed mechanism was discussed and photos of the entire process were shown. The materials (AgNO3 and AgNP) were characterized by UV–Vis, SEM and XRD. The UV–Vis exhibit a strong broad peak at 417 nm due the surface plasmon resonance (SPR) absorption band of AgNP. The SEM images showed spherical nanoparticles, non-aggregates and with an average diameter of 50 - 140 nm. The XRD of AgNP presented four main characteristic peaks for silver corresponding to (111), (200), (220) and (311) planes, confirming the cubic (FCC) silver. The AgNP ink has an excellent conductivity, with an average ohmic resistance of 1.53 Ω. Finally, the AgNP ink was tested in the fabrication of reference electrodes and the analytical response was higher than the conventional Ag/AgCl reference electrode.

International audience; Enzymatic biofuel cells are emerging technologies which gain a lot of interest as a power source for implantable devices. Effective enzyme wiring and simplification of the cell architecture are the main limitations of the fuel cell development nowadays. In the present study, spray coating was used as a reliable process to produce flexible biocathodes. That was achieved through spray coating of a conductive ink formulated by surfactant assisted carbon nanotubes dispersion. A thin continuous layer of carbon nanotubes (CNTs) was successfully coated on top of a gas diffusion layer paper. The film thickness was modulated by varying the CNT load in the ink and the number of deposited layers. It varied between 1 and 7.8 μm for a number of deposited layers between 5 and 100. Laccase enzyme was then wired to printed CNT electrodes thanks to the host-guest interaction between the hydrophobic pocket of laccase and pyrene-adamantane. Electrochemical investigations showed that laccase was effectively wired to the CNTs and presented a favorable orientation toward oxygen reduction. The biocathode current density was dependent of the number of deposited CNT layers and reached an optimum at 170 μA cm−2 for 50 deposited layers.

In this work, we have grown ZnO/CuO nanoflowers on graphene printed paper substrates by the hydrothermal method. The hypothesis of the present work is the role of ZnO and CuO composited graphene structures as affordable substrates for room temperature ammonia gas sensor. To fabricate the conductive substrate, the biomass derived graphene has been formulated as conductive ink and printed (20 µm) on the paper substrate. The optical, structural, and morphological studies confirm the formation of hierarchical nanoflower like ZnO/CuO@graphene substrate. The chemiresistive gas sensor studies evident that, the ZnO/CuO@graphene substrates have higher sensing performance in the presence of ammonia (4.9%) for the concentration as low as 5 ppm at room temperature. It also shows a quick response and recovery time of 4.1 s and 2 s, respectively. Our present method will be an effective methodology for the fabrication of cost-effective and rapid detection of ammonia gas in the ambient environment and can be also further suitable for non-invasive earlier diagnosis of diseases from exhaled breath.

In this paper, a novel antenna circuit based metamaterial (MTM) structures is proposed for Wi-Fi applications. The antenna consists of two dipoles with 3 × 5 Hilbert-shaped MTM array printed with Sliver Nanoparticles Conductive Ink (SNPCI). The antenna substrate is mainly created from INP composite of: Iraqi Palm Tree Remnants (IPTR) and Nickel Oxide Nanoparticles (NONP) with Polyethylene (PE) mixture. The relative permittivity (er) and permeability (μr) are measured using an open-stub microstrip resonator to find er = 3.106 − j0.0314 and μr = 1.548 − j0.0907 at the frequency band of interest. Numerically, Finite Integral Technique (FIT) and Finite Element Method (FEM) of CSTMWS and HFSS formulations, respectively, are invoked to investigate the antenna performance. Experimentally, the antenna exhibits two resonances, |S11

Silver nanoparticle (AgNP) inks are the most commonly used conductive ink for printed conductive tracks. However, the ink stability against aggregation and sedimentation is poor and results in short shelf life, severe nozzle clogging, and bad printing qualities. Herein, a new method is developed to improve the stability of AgNP inks. In this work, a water-in-oil type emulsion is used as a carrier for water-based silver nanoparticles. Different water/surfactant ratio are examined for the complete AgNP uptake in water nano droplets. The morphology of AgNP after emulsification is carefully examined with electro-microscopy to elucidate the particle engulfment in water. The encapsulated AgNP show a much lower sedimentation rate due to the greatly reduced overall density of encapsulated AgNPs/water droplets. Moreover, the water/oil interfaces around AgNPs prevent aggregations, and thus leads to better long-term ink stability. The physical properties of AgNP emulsion meet the requirement of the printer and stable inkjet droplet can be produced. Conductive tracks with electrical resistance 4.92 μΩ-cm and line width 170 µm can be printed on photo papers, which demonstrates the potential of the emulsion for inkjet printing application.

Screen printing is widely used to form conductive patterns due to its simple process, inexpensive equipment and masks, and fewer printing errors. In the field of electronics, there has recently been a growing demand to print both low-width and high-thickness electrodes, not only on flat surfaces but also on cylindrically curved ones. However, screen printing cannot form fine patterns due to ink bleeding, and in principle, printing on concave surfaces is impossible with conventional screen printing. Further, overprinting forms a thick pattern that requires subjecting the conductive ink to a drying process before printing the next layer of ink, leading to longer processing times. To address these issues, we developed an advanced screen printing technique called screen-offset curved-surface printing to form fine patterns on a curved substrate. In this method, ink is screen-printed onto a roll-type silicone blanket, and the ink is then transferred from the blanket onto a final substrate. During the transfer process, the roll-type blanket is moved in the vertical direction with a rotational motion along the surface of the curved substrate. It is this compound motion of the blanket that enables printing on a curved surface. Moreover, a simple overprinting technique for thick patterns was successfully performed on the curved substrate. This technique leverages the fact that the silicone blanket absorbs the organic solvents in the ink; the increase in the viscosity of the first layer of ink, owing to the solvent absorption, enables the next layer of ink to be easily overprinted on the blanket. In this paper, the developed printing method is presented in detail.

A conductive textile was fabricated by vacuum-filtration using conductive ink prepared from multi-walled carbon nanotubes. The fabricated conductive textile was evaluated as its resistance varied while it was subjected to repeat stretching at strain rates of 0% to 20%. The textile samples showed resistance variations of less than ±3% after 10,000 cycles of stretching, and the pulse of the resistance variation at a strain rate of 0%–20% remained uniform during the stretching cycles. A motion-sensing glove fabricated with the conductive textile showed that the pulse of the oscilloscope changed accurately with movements of the fingers. These results show that the conductive textile prepared in this study can be applied to motion-sensing products.

Recently, triboelectric nanogenerator (TENG) has aroused considerable interest due to various advantages. Particularly, one benefit which sand out is that the triboelectric pair of TENG is very tolerant to the material composition. Thus, it is possible and significant to develop cost-effective TENG using commercial and inexpensive material. In this work, we present a paper TENG by repeated folding completely using commercially available commodity materials, such as paper, brush pen, Teflon tape, and conductive ink. Paper is used as functionally triboelectric pair and spring-like supporting structure. The stacked paper TENG is fabricated and large enhancement of output performance is observed. The generated electric outputs have been used to directly light-up commercial LEDs. The proposed TENG has demonstrated simplicity and cost-effective, which is suitable for flexible electronics.

Printing high-resolution microwave passive devices directly on textile surfaces presents many challenges due to the high surface roughness and porosity of textile materials. This paper explains in detail physical and electromagnetic characterization of screen-printed coplanar waveguides (CPWs) on nonwoven textiles with a surface roughness of approximately ∼18 μm. Three different screen mesh counts (mesh opening unit) are used to screen print CPWs with five different resolutions. A screen printable silver paste is used as a conductive ink during the screen printing process. The difference in screen mesh counts affects the line resolution, thickness, conformity, and overall power transferring capacity of printed CPWs. A print resolution of 220 μm as the gap between the parallel lines of CPWs is achieved in this work without any surface modification of textile media. The surface roughness of the printed silver track is very similar to the base fabric (18 μm) when the screen with 305 mesh-count is selected for printing. Additionally, the thickness of the ink on the fabric is most conformal and lowest (23.4 μm) for the similar selection of screen mesh count. Fabricated CPWs are characterized for signals from 0.5 GHz to 10 GHz and compared to electromagnetic 3D simulation results. This paper also identifies minute printing faults in the 3D structure of the printed CPWs and correlates that with the scattering parameters of the transmission lines. Simulated and experimental data prove that a well-designed and process optimized printed nonwoven-based CPW works well (i.e. below 3 dB of insertion loss) for frequencies ranging from 0.5 GHz to 7 GHz.

Chitosan (CS)/carbon black (CB) composite sponges with high electrical conductivity and strain sensing sensitivity are prepared by combining solution-mixing and freeze-drying techniques. CB nanoparticles with diameter of ~40 nm play the role of a conductive component in the CS/CB composites. CB can form a continuous filler network in CS, which leads to the increase in viscosity and shear modulus. When writing and drying the CS/CB conductive ink, conductive tracks are obtained. With the increase in CB content, the density, electrical conductivity, compressive properties, and thermal stability of CS sponges are improved. The X-ray diffraction and Fourier transforms infrared spectroscopy results show CB are successfully compounded into CS matrix. The addition of CB leads to a slight decrease in the porosity of CS sponges. Sensing performances of CS/CB composite sponges are investigated by detecting various human activities including pronouncing, breathing, and joint bending. CS/CB composite sponges show good sensitivity and stability after several hundred loops. CS/CB composite sponges combine the advantages of low-cost, easy fabricating process, flexible, and high performance, which make them show great potentials in highly sensitive strain sensor. Keywords: Chitosan, Carbon black, Sensor, Mechanical property, Structure, Sensitivity

The drop on demand direct writing technology is the most efficient alternative to the traditional technologies for fabricating electronic devices on soft substrates. This piezo driven direct deposition technology requires preparation of a conductive ink comprising stable suspension of nanoparticles. In the present work, we have synthesized nearly mono-sized silver nanoparticles by chemical reduction method in presence of a capping agent for preparing conductive ink. The particle size distribution, viscosity and wettability (on the substrate) of the colloidal silver suspension were measured. The morphology of the silver nanoparticles was characterized by FESEM and TEM, respectively. (c) 2017 Elsevier Ltd. All rights reserved.

In this study, waste poly(ethylene terephthalate) (PET) bottle was depolymerized using excess ethylene glycol (EG) in the presence of cobalt(II) acetate tetrahydrate ((CH3COO)2Co·4H2O) as a catalyst. It was found that the reacted products consist mainly of bis-2-hydroxy ethylene terephthalate (BHET) monomer. Poly(ethylene terephthalate)-poly(lactic acid) (PET-PLA) copolymers were synthesized by the reaction of BHET with L-lactic acid (LLA) monomers using the catalytic system. The samples were analyzed by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The 1H and 13C NMR studies confirm the incorporation of lactate units in PET chains after reaction. Further, we report the use of graphene conductive ink and PET-PLA as the electrochromic (EC) device. Copolymer film was coated with graphene ink by spin coating method. Our results primarily indicate that the configuration presents an easy and expeditious way.

Emerging applications of drop-on-demand (DOD) inkjet printing, such as printed electronics and bioprinting, are leading to an ever-increasing development of diverse functional inks with complex chemical and rheological properties, especially viscoelastic polymers. Forming droplets with desirable velocity and volume as well as excellent reliability is of great importance for successful printing. In this study, the dynamics and performance of droplet formation during DOD inkjet printing of viscoelastic ink were investigated by employing the piezoelectric inkjet technology to print a conductive polymer ink under various excitation waveform parameters. Four distinct droplet formation regimes were identified, namely, no droplet formation, a single droplet, one satellite droplet, and multiple satellite droplets. A process dynamics-related dimensionless number (Wj) was proposed to construct an operating phase diagram on droplet formation and quantify the transition of droplet formation regimes. The effects of bipolar waveform parameters on droplet formation were systematically examined in terms of Wj, droplet velocity, and droplet diameter. Moreover, the printing of microlines and micropatterns was precisely controlled under well-formed droplets. This study could support fully understanding the droplet formation dynamics during DOD inkjet printing of viscoelastic inks to guide generating desirable droplets of functional ink and improve the performance and function of inkjet-printed devices.

The article presents end evaluates foil transducers, namely conductive rubber and conductive ink, and their use in the pressure distribution measurement system Plantograf. The ability of both materials to act as transducer between pressure and electrical quantities is assessed by means of measurement on a robotized workspace; two electrode types and various ink layer thicknesses are studied. Basing on the measurements, we present graphically the dependency of the electrical resistance of the materials on the applied pressure. Although both materials proved their ability to act as a transducer in a planar sensor, they both exhibit some limitations. In case of rubber it is limited pressure range up to ca. 1400 kPa and significant hysteresis of the material. The main limiting factor with conductive ink is its poor adherence to the electrodes, which poses important problem for its practical use, although this material evinces better transfer characteristics, particularly in the configuration with 7 μm ink layer and LD type electrode.

A simple and inexpensive procedure of paper-based electrode (PE) fabrication using A4 size conventional paper, nail polish and carbon powder is reported. The device was prepared by spreading the carbon conductive ink directly onto the paper substrate using a paint-brush. The best composition of the conductive ink was 80:20% (m:m) carbon powder: nail polish and the best device was obtained with 100 mg (2.5 mg cm−2) of carbon conductive ink spread on the paper piece. The proposed device showed satisfactory stability in acidic, neutral and alkaline medium in presence of ferrocyanide ion used as electrochemical probe. Dopamine was selected as a target compound to evaluate the possibility of using the proposed device for electroanalytical purposes. Differential pulse voltammetry was used in these studies and dopamine detection was achieved at +0.13 V vs. Ag/AgClsat in phosphate buffer solution pH = 7 with a detection limit of 5.2 μmol L−1. The proposed device represents an interesting advance in the field of PE construction since it combines satisfactory electrochemical stability and electroanalytical performance with simplicity and widely available low-cost materials. Moreover, chemical modifiers can be easily added to the conductive ink. Therefore, this versatile device brings exciting possibilities for future electroanalytical applications mainly for those that require small and/or flexible devices, such as the amperometric detection in microfluidic systems.

The growth in the demand for mass analysis, in a fast and safe way, with good reliability and low cost has aroused great scientific interest in the search for new devices that prioritize precision and time. In this sense, this work presents a simple, disposable, and easy-to-use electrochemical sensor, developed on a waterproof paper substrate with a conductive ink based on shellac, a resin of natural origin, and graphite. The conductive ink was obtained through a simple mixture of its components and deposited on the paper substrate, being ready to use after a drying period. The new sensor was employed for the electrochemical detection of sulfamethoxazole (SMX), an antibiotic belonging to the class of sulfonamides, which presents great importance due to its direct impact on the flow of the food chain and is, therefore, commonly found as a metabolic residue in environmental and food samples. Using the differential pulse voltammetry technique, a linear range of 5.0 μmol L−1–100 μmol L−1 and a limit of detection of 0.4 μmol L−1 were obtained. The electrochemical sensor was also employed for the analysis of SMX in water and milk samples, and recovery values between 91 and 110% were obtained, proving that the development and application of the new conductive ink proposed for the fabrication of disposable devices provided an efficient electrochemical detection of SMX in the applied samples.

Flexible pressure sensors are promising for biomedical diagnosis and health monitoring, but most of such sensors meet with problems of one kind or another, such as counterfeit sensitivity, poor durability, expensive fabrication cost and trade-off between sensitivity and sensing range. Herein, a high-performance flexible pressure sensor microstructured with femtosecond filamentating pulses is assembled to realize robust physiological signal monitoring. The sensing mechanism is based on the change of contact resistance between the patterned silver conductive ink thin layer and the laser filament-microstructured polydimethylsiloxane film coated with single-walled carbon nanotubes. The sensor exhibits a maximum sensitivity of 0.266 kPa−1, a broad range of up to 160 kPa and an excellent stability. Benefiting from the aforementioned advantages, the sensor is used with success to detect a variety of human physiological signals, such as real-time artery pulse and throat muscle movement. Moreover, with the assistance of principle component analysis algorithm, it is demonstrated that the sensor can unambiguously distinguish different phonations, making it high potential for application in physiological analysis systems.

Additive Manufacturing has increased our ability to fabricate complex shapes and multi-material structures. Epoxy is excellent as the base for structural composite materials. Furthermore, carbon nanotube (CNT) is an outstanding filler due to its unique properties and functionalities. Here, conductive epoxy-nanoclay-CNT nanocomposite structures were fabricated by direct-write 3D printing. In this process, 3D-printable composite inks were synthesized by incorporation of nanoclay and different concentrations of CNTs – 0.25, 0.5, and 1 vol%, 0.43, 0.86, and 1.7 wt% – in epoxy. CNTs were found to significantly improve the electrical and mechanical properties. Rheological characterization of the inks revealed a shear-thinning behavior for all the nanocomposite inks and an increase in the complex viscosity, storage, and loss moduli with the incorporation of CNTs. The CNT concentration of 0.5 vol% was found to be the optimum condition for enhancement of mechanical properties; an average increase of 61%, 59%, and 31% was measured for flexural strength, flexural modulus, and tensile strength, respectively, compared to the 3D printed epoxy-nanoclay nanocomposite structures. The electrical conductivity of 2.4 × 10−8 and 2.2 × 10−6 S/cm was measured for the nanocomposites containing 0.5 and 1 vol% CNTs, respectively. Multi-scale characterization of the morphology revealed partial alignment of CNTs in the direction of printing, CNT pull-out and breakage at the fracture surfaces, and nano-scale interactions of the constituents, all of which contribute to the superiority of the nanocomposite with CNTs. The findings show the promise of this ink material and printing method for various applications such as aerospace structures and electronics.

A shear exfoliation of graphite in Arabic gum solution is one of the interesting non-toxic methods for production of few-layer graphene. While the utilization of Arabic-based graphene is mainly as conductive ink for inkjet or screen printing of circuit for sensing or electronic device, it is noted that there is lack of works reporting on the role of this polysaccharide class-based graphene for smart vapour-driven sensing film. In this brief report, the effect of Arabic gum/graphene presence on the cosmetic oil control film (Clean and Clear®) for bending-unbending performance of vapour-driven film was investigated. It is discovered that the film was able to complete a bending cycle within 13 s while the maximum recorded bending radius was measured at 0.48 cm after exposure to tetrahydrofuran (THF) in controlled environment condition (50%rh and 25 °C). By controlling the distance between THF source and the smart film, we further show the crawling motion of this film that resembling leech with a speed of 0.5 cm/48 s.

Sulfated nanocellulose (SNC) is used as a dispersant instead of poly(styrene sulfonate) (PSS) to prepare poly(3,4-ethylenedioxythiophene) (PEDOT) dispersion by in-situ polymerization. Due to the excellent electronegativity provided by the sulfate groups on the cellulose chain and the colloidal stability of nanocellulose, the obtained PEDOT:SNC dispersions exhibit controllable conductivity, high stability with less dispersant and even good redispersibility. In addition, these dispersions show excellent printing suitability on a variety of substrates, proving their great potential to be applied as conductive ink for electronic circuit printing. Based on the outstanding forming ability of SNC, high performance PEDOT/SNC nanocomposite film can be fabricated from the PEDOT:SNC dispersion directly, which can serve as high-performance multifunctional sensors to external stimuli.

Screen printing has various industrial applications owing to its simple process and low production cost. With advancement in electronic devices, the demand for fine electrode patterns is gradually increasing. In this study, a novel method for fabricating a hybrid fine metal mask (HFMM) was developed to enable the screen printing of fine electrode patterns. The HFMM was designed to combine the advantages of the conventional screen mask and metal stencils; it was fabricated through photolithography and the electroforming process. The HFMM comprised three parts: a stencil, a bridge, and an anti-sticking feature. A conductive ink, which was passed through the stencil feature, was deposited on the substrate and the bridge feature helped increase the mechanical rigidity of the HFMM. The anti-sticking feature was fabricated for the easy separation of the HFMM from the substrate during the printing process. In this study, the printing feasibility of HFMM to the screen printing process was tested to fabricate fine electrodes with a line width of approximately 10 μm, and the printing and electrical properties of the electrodes were evaluated. The screen printing process with HFMM could be applied to fabricate various functional electrodes, such as stretchable and transparent electrodes.

An all printed flexible, energy-efficient heater was fabricated using a conductive ink principally made of MWCNT. Herein, a systematic investigation on employing PEDOT:PSS as an effective binder and dispersant for affordable conductive ink manufacturing was carried out. Screen printable room temperature curing formulation made of MWCNT and PEDOT:PSS is being reported for the first time. The ink's enhanced stability is contributed by the π-π interaction between MWCNT and PEDOT:PSS. The printed conductive traces showed a sheet resistance of 51.31 ± 0.25 Ω/□ on Mylar substrate, ideal for flexible heater applications. The screen printed flexible heater based on MWCNT-PEDOT:PSS nanocomposite has impressive energy efficiency and thermal stability, generating a peak temperature of 136 °C at the expense of only 0.137 W/cm2.

In this study, supercapacitors based on magnetic conductive polymer-graphene nanocomposites were investigated. The graphene was synthesized from graphite oxide and graphite by Hummers and electrochemical exfoliation method, respectively. The graphene was characterized using Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction. The nanocomposite was obtained by mixing graphene with polypyrrole or magnetic polypyrrole. The conductive ink consisted of the nanocomposite, solvent and binder. The supercapacitor electrodes were manufactured with the conductive ink by using copper foil. Supercapacitor cells were composed of the separator (PTFE) and electrolyte (ionic liquid materials or acids). The cells were characterized by measurement of the specific capacitance and charge-discharge characteristics. Cyclic Voltammogram (CV) plots and scan rate studies showed a good cell structure and charge-discharge characteristics. So far, 255 F/g specific capacitance values have been achieved. Electrochemical impedance spectroscopy analysis showed a healthy cell performance and a fast capacitor response.

Conductive copper inks have attracted much attention as low-cost replacement for the currently used silver inks for printed electronics. The copper inks should be stable to oxidation at all stages of fabrication of conductive patterns: ink formulation and storage, printing, and post-printing treatment. In the present study, air-stable copper-silver core-shell (Cu@Ag) submicron particles were utilized in conductive ink formulations. To improve the conductivity of the resulting Cu@Ag coatings, the effect of various carboxylic acids was evaluated. It was found that all acids led to decreased resistivity after sintering at elevated temperatures, while the lowest value was only 4 times higher than the bulk resistivity at 3 wt% of oleic. The mechanism governing the effect of carboxylic acids is discussed, in view of possible stabilizer exchange and oxide dissolution.

Silver nanowire (AgNW) ink has great influence on the performance of the resulting AgNW-based conductive film, especially for the large-scale roll-to-roll processed films. However, AgNW inks made by researchers are almost immature because there is not a clear research procedure for the development of qualified inks. In this work, electric double layer model, Young equation, bubble theory, percolation theory, Rhodes & Orchad equation, Kelvin equation and other theoretical models were introduced successively to describe those processes which additives in inks should adjust. Based on the guidance of these theories, additives were determined successively and an optimized light grey ink with the composition of 0.4% AgNW + 0.2% 2-amino-2-methyl-1-propanol + 0.01% Zonyl FSO-100 + 1.5% diacetone alcohol + 5% 1,4-dioxane + 92.89% isopropyl alcohol was obtained. Except for trace amount of Zonyl FSO-100, other additives could be easily eliminated at low temperature (110 °C), which could retain the original properties of AgNW furthest and greatly lower the dosage of AgNW in inks. Based on this ink, excellent AgNW/PET composite film was prepared. The sheet resistance, transmittance and haze of this film were 29.5 Ω/sq, 88.9% and 1.49% respectively. Finally, touch screens (180 mm × 105 mm) and tablets (10 inches) were prepared from our films and showed good performance. These results demonstrated that excellent AgNW ink could be developed through our research procedure. Our studies not only produce an excellent AgNW ink, but also provide a systematic research procedure and series of theoretical models for many kinds of conductive inks.

The temperature effect on the electrical characteristics and surface morphology of printed silver ink was investigated for laser irradiation with various laser scanning speeds and intensities. Inkjet-printed silver lines onto a glass substrate were irradiated with a 532 nm continuous wave. The electrical resistance was measured after laser sintering with various scanning speeds and intensities. The temperature field was invoked in the printed silver ink line by laser scanning sintering and this was predicted by numerical analysis. This temperature field show a quasi-steady state behavior since laser irradiation can be considered as a moving heat source. Field emission scanning electron microscope images were then examined with calculated temperatures of printed silver ink. The relation of surface morphology with temperature field were discussed. The effect of a laser scanning speed on the specific resistance of the conductive ink line was intensively investigated.

We report on the synthesis of copper-silver core-shell (Cu@Ag) particles with about 1 μm-diameter Cu core coated with a thin (∼20 nm) silver shell, for application in printed electronics as low cost conductive ink. The process is based on using the environmentally friendly sodium formaldehyde sulfoxylate dehydrate as a reducing agent for copper ions and two types of polymeric stabilizers (nonionic PVP and anionic PAA). The formation of core-shell particles is followed by transmetallation reaction on the surface of the Cu particles, where copper atoms function as the reducer for silver ions. Characterization of the submicron particles by SEM, EDS and XRD confirm the core-shell structure. The resulting Cu@Ag particles enable overcoming a major challenge in copper ink, their rapid oxidation in air. It was found that ink formulations based on propylene glycol as the liquid vehicle and containing a silicone based wetting agent possesses the optimal characteristics (wetting, sintering) for printing on a glass substrate. To obtain conductive metallic structures, thermal sintering of metallic patterns was used. The Cu@Ag coating are stable to oxidation for at least 6 months at room temperature, and also during sintering process which is carried out at temperatures up to 250 °C. The conductivity of Cu@Ag coatings after sintering at 250 °C was high, 16% of that for bulk copper.

A novel device for targeting proteins with a Molecularly-Imprinted Polymer (MIP) recognition material is presented herein, by employing wax paper with conductive ink as background support. Cellulose paper was modified with paraffin wax to make it waterproof, and afterwards covered by a carbon ink to make it conductive, achieving the goal to make easy and low cost supports, and, in this case, with good detection features. Bovine Serum Albumin (BSA) was used herein as target protein. Albumin has an important role in the human body and BSA is normally used as its model protein because of its good stability and low cost. The development of BSA detection systems is important in various fields, such as biochemistry, medicine and pharmacy. Raman measurements were conducted during all preparation stages of the recognition material and electrochemical assays were used to evaluate the analytical performance of the sensor. The assembly of the device was optimized by employing different polymerization timings and monomers of different chemistries and charges. In general, longer polymerization periods and the use of a positively charged monomer benefited the analytical response. The results obtained within different calibrations indicated a linear response over a wide concentration range, from 0.005 to 100 mg/mL of BSA in buffer solution. In addition, the analytical evaluation of the device under several background solutions, including synthetic and real urine, supported the good performance of the sensor and pointed out that the principle of sensor assembly may be extended to other proteins in urine. In addition, the detection capabilities of the device proposed herein are better than other BSA sensing devices relying on electrochemical transduction.

Improving the performance of electrochemical sensors based on indium tin oxide (ITO) can be achievedvia intrinsically conducting polymers such as poly (3, 4 ethylenedioxythiophene): polystyrene sulfonate(PEDOT:PSS). However micropatterning of PEDOT:PSS to form microelectrodes on such substrates hasbeen challenging. Here we demonstrate a technique for the precise micropatterning of a conductive ink onITO using photolithography to realize a covalently-attached ion-transport matrix for stable biosensing.This micropatterning is accomplished using an all water-based and ambient temperature processing.We present electrochemical characterization of the material composite via electrochemical impedancespectroscopy, cyclic voltammetry and differential pulse voltammetry. A sensitive sensor is fabricated forthe neurotransmitter dopamine, with a linear range from 1 to 50 M. The sensor signal is very stableunder cyclic increase and decrease in the concentration of dopamine. This sensing can be achieved evenin the presence of ascorbic acid at 1000 times higher concentration than dopamine. Further, enzymes canbe immobilized in the conductive matrix to form highly selective sensors. Such robust micropatterningstrategies can greatly expand the use of conducting polymer substrates in biosensing applications., info:eu-repo/semantics/publishedVersion