Nano-silver Ink Research Articles

Aptasensing of rivaroxaban in human plasma using KCC-1-NH-CS2 modified conductive nano-ink: A new biosensor

An innovative paper-based electrochemical aptasensor has been developed for the detection of Rivaroxaban (RIV) in human plasma samples. The sensor is fabricated using a novel prob by encapsulating aptamer-aminated on dendritic fibrous nano-silica (KCC-1-NH-CS2) particles. The prob is then immobilized on the functionalized silver nano-ink electrode.. The resulting redox reaction on the prob was subsequently evaluated using square wave voltammetry, differential pulse voltammetry, and chronoamperometry. Under optimized condition and using a label-free strategy, the aptasensor exhibited suitable sensitivity and specificity for detecting RIV with a linear range of 10 to 1000 nM and a lower limit of quantification (LLOQ) of 10 nM. The engineered aptasensing platform shows great potential for the fabrication of other cost-effective, sensitive, and portable biosensors for the pharmaceutical and biomedical analysis.

Silver Nano-Inks Synthesized with Biobased Polymers for High-Resolution Electrohydrodynamic Printing Toward In-Space Manufacturing.

Electrohydrodynamic (EHD) printing is an additive manufacturing technique capable of producing micro/nanoscale features by precisely jetting ink under an electric field. However, as a new technique compared to more conventional methods, commercially available inks designed and optimized for EHD are currently very limited. To address this challenge, a new silver nanoink platform was developed by synthesizing silver nanoparticles in situ with biobased polymer 2-hydroxyethyl cellulose (HEC). Typically used as a thickening agent, HEC is cost-effect, biocompatible, and versatile in developing inks that meet the rheology criteria for high-resolution EHD jetting. This approach significantly outperforms the traditional use of polyvinylpyrrolidone (PVP), enabling the stabilization of high solids content (>50 wt %) nanoinks for over 10 months with an HEC dosage 20 times lower than that required by PVP. The HEC-synthesized silver ink displays excellent electrical properties, yielding resistivities as low as 2.81 μΩ cm upon sintering, less than twice that of pure silver. Additionally, the capability to sinter at low temperatures (<200 °C) enables the use of this ink on polymer substrates for flexible devices. The synthesized nanoinks were also found to be capable of producing precise, high-resolution features by EHD printing with smooth lines narrower than 5 μm printed using a 100 μm nozzle. Additionally, a semiempirical model was developed to reveal the relationship between printing resolution, ink properties, and printing parameters, enabling precise printing control. Moreover, for the first time, the unique ability of EHD to achieve precise fabrication under microgravity was conclusively demonstrated through a parabolic flight test utilizing the HEC-based nanoinks. The study greatly expands the potential of printing thin films for the on-demand manufacturing of electronic devices in space.

Miniaturizing Nanotoxicity Assays in Daphnids.

The rapid progress of the modern world has resulted in new materials and products created at an accelerating pace. As such, nanoparticles have widespread applications and often find their way into the aquatic ecosystem. In the case of freshwater ecosystems, one of the commonly used bioindicators species used for pollution assessment is Daphnid magna. The Organization for Economic Co-operation and Development (OECD), and other organizations such as the European Chemicals Agency (ECHA) and Environmental Protection Agency (EPA), have set guidelines for acute toxicity testing in daphnids that are severely lacking in terms of information on the characteristics of the exposure vessel when studying the adverse effects of nanoparticles (NPs). Understanding the toxicity mechanisms of nanomaterials is imperative given the scarcity of information on their adverse effects. Furthermore, miniaturization of nanotoxicity assays can reduce the number of daphnids used, as well as the cost and nanomaterial waste, and provide results even at the individual animal level with enhanced reproducibility of testing. In this study, the impact of the exposure vessel on the observed physiological changes of daphnids was investigated for a silver nano ink. Exposures in eleven commercially available vessels; nine made of plastic and two made of glass were compared for 24 h. The effect of surface to volume ratio of the exposure vessel and the animal number or "crowding" during exposure was investigated in the context of miniaturizing biomarker assays as alternatives to traditional experimental setups in Daphnid magna. Toxicity curves showed differences depending on the vessel used, while a novel feeding rate assay and the activity of key enzymes were assessed as physiology endpoints.

A compact tri-notched flexible UWB antenna based on an inkjet-printable and plasma-activated silver nano ink

The rapid development of ultrawideband (UWB) communication systems has resulted in increasing performance requirements for the antenna system. In addition to a wide bandwidth, fast propagation rates and compact dimensions, flexibility, wearability or portability are also desirable for UWB antennas, as are excellent notch characteristics. Although progress has been made in the development of flexible/wearable antennas desired notch properties are still rather limited. Moreover, most presently available flexible UWB antennas are fabricated using environmentally not attractive subtractive etching-based processes. The usage of facile additive sustainably inkjet printing processes also utilizing low temperature plasma-activated conductive inks is rarely reported. In addition, the currently used tri-notched flexible UWB antenna designs have a relatively large footprint, which poses difficulties when integrated into miniaturized and compact communication devices. In this work, a silver nano ink is used to fabricate the antenna via inkjet printing and an efficient plasma sintering procedure. For the targeted UWB applications miniaturized tri-notched flexible antenna is realized on a flexible polyethylene terephthalate (PET) substrate with a compact size of 17.6 mm × 16 mm × 0.12 mm. The antenna operates in the UWB frequency band (2.9–10.61 GHz), and can shield interferences from WiMAX (3.3–3.6 GHz), WLAN (5.150–5.825 GHz) and X-uplink (7.9–8.4 GHz) bands, as well as exhibits a certain of bendability. Three nested "C" slots of different sizes were adopted to achieve notch features. The simulation and test results demonstrate that the proposed antenna can generate signal radiation in the desired UWB frequency band while retaining the desired notch properties and having acceptable SAR values on-body, making it a viable candidate for usage in flexible or wearable communication transmission devices. The research provides a facile and highly efficient method for fabricating flexible/wearable UWB antennas, that is, the effective combination of inkjet printing processing, flexible substrates, low temperature-activated conductive ink and antenna structure design.

An innovative transportable immune device for the recognition of α-synuclein using KCC-1-nPr-CS2 modified silver nano-ink: integration of pen-on-paper technology with biosensing toward early-stage diagnosis of Parkinson's disease.

Parkinson's disease (PD), the second most frequent neurodegenerative illness, is a neurological ailment that produces unintentional or uncontrolled body movements, which should be diagnosed in its early stages to hinder the progression. Monitoring the concentration of α-synuclein (α-Syn) in body fluids can be one of the most efficient ways for PD early detection. In this work, a paper-based electrochemical immunosensor was designed for α-Syn bio-assay in human plasma samples based on encapsulation of the biotinylated antibody on novel dendritic fibrous nanosilica ((KCC-1-nPr-CS2)-Ab). For this purpose, a three-electrode system was prepared using stabilization of silver nano-ink on photographic paper. Then, the (KCC-1-NH-CS2)-Ab was immobilized on its surface and used to detect the target antigen (α-Syn). After characterization of the prepared substrate by FE-SEM and EDS, the redox behavior of the biosensor was evaluated using chronoamperometry techniques. Under optimal experimental conditions and using a label-free strategy, the engineered immunosensor showed a linear relationship between peak current and antigen concentration in the linear range from 0.002 to 128 ng mL-1 with the lower limit of quantification of 0.002 ng mL-1. Moreover, this work involves unprecedented use of conductive nano-inks for the manufacture of α-Syn immunosensor, which is aided by the use of a mesoporous silicate dendrimer in encapsulating the α-Syn antibody, thus offering a robust and simple point-of-care device for early PD diagnosis. The ability of the proposed platform to detect small amounts of α-Syn offers a promising approach to developing low-cost, sensitive, and transportable biosensors for Parkinson's disease screening in its early stages.

Print Durability and Recyclability of Label Paper Equipped with Printed RFID Antenna

Labels are a crucial component of products, offering informational content and attractive visuals; therefore, the durability of the print is an important quality requirement. On the other hand, in accordance with eco-design, the recyclability of printed labels is vital. In our research, the focus was on the assessment of the durability, recyclability, and deinkability of printed label paper equipped with printed RFID tags. The determined color fastness of electrophotographic prints affected by various environmental factors showed good resistance to dry rubbing and, in most cases, light and moist–heat treatment, confirming the applicability of digital printing on self-adhesive biodegradable paper labels. In the second part of this study, recyclability was assessed, and a comparison between the deinkability of the offset and digital prints and two conductive functional inks was conducted. Good deinkability was observed for the printed RFID antennas on both the offset and electrographic prints, with only a small deterioration in optical properties, especially when nano-silver conductive ink was used. The study highlights the importance of the selection of materials and printing techniques when considering the environmental impact of printed electronics. The results showed that INGEDE 11 is a suitable deinking method for printed RFID antennas on offset and electrographic prints.

Multi-layered micro-patterns co-printed with Ag@CuO nano-ink for flexible devices

Abstract Silver (Ag) nano-ink is widely used to fabricate the micro-patterns of flexible electronic devices owing to its excellent conductivity and stability. However, the cost of micro-patterns prepared with silver nano-ink is high. Here, multi-layered, multi-inked (silver@copper oxide) micro-patterns were co-printed layer by layer using an in-house silver nano-ink and commercial copper oxide (CuO) nano-ink. The prepared micro-patterns were solidified by laser sintering. Among the co-printed micro-patterns, the micro-pattern with a top layer of copper (1CuO@2Ag) had the lowest resistance, which was 13.1 Ω cm–1. Additionally, 1CuO@2Ag had the smoothest topography and lowest porosity, which was attributed to effective sintering at the optimal laser power (3 W) for all co-printed micropatterns owing to the high absorptivity and low reflectivity of copper. Moreover, after 500, 1000, and 1500 cycles of fatigue testing, the resistance of 1CuO@2Ag increased by 1.5%, 8.4%, and 13.7%, respectively, indicating good reliability. The proposed method lays the foundation for further studies on Ag@CuO composites for micro-pattern preparation.

Direct pen writing and atomic-scale molecular dynamics simulation study of a novel silver nano-ink

Direct pen writing and atomic-scale molecular dynamics simulation study of a novel silver nano-ink

Large-Area Inkjet-Printed Flexible Hybrid Electrodes with Photonic Sintered Silver Grids/High Conductive Polymer.

The field of printed organic electronics has not only made flexible devices accessible but also allows the production process toward a high throughput industrial scale. The current research involves the inkjet-printing of an indium tin oxide-free large-area flexible hybrid electrode compose of a high conductivity organic layer (PEDOT: PSS) as a main electrode and inorganic silver nanoparticles-based grid/film for the auxiliary electrode. The current bottleneck in the roll-to-roll production of printed electronics is the time required for the conductive inks to dry and sinter. Flash sintering is used to dry nano-silver conductive ink to 77.6mΩ□-1 sheet resistance in <20ms, the quickest annealing procedure, without damaging flexible substrates. Flexible organic light-emitting diodes (OLEDs) are created with a large active area (500mm2 ) to demonstrate the efficacy of the flexible hybrid electrodes and the excellent bending stability (4mm bending radius) of OLEDs. Maximum current efficiency of 19.58cdA-1 and a maximum luminescence of 8708cdm-2 at a low turn-on voltage of 3.1V for the small-area (16mm2 ) OLEDs are achieved. This method is promising for reducing indium consumption and paving the way for creating new high throughout hybrid electrodes for large-area flexible printed electronics.

Additive manufacturing of low-temperature co-fired ceramic substrates and surface conductors based on material jetting

Integrated manufacturing of ceramic substrates and surface conductors using 3D material jetting (MJ) technology is a novel additive manufacturing route for low-temperature co-fired ceramics (LTCC). This study evaluates the rheological and jetting properties of LTCC nanoceramic inks with varying solids contents. Ceramic inks with 35 % solid content were found to be the optimal choice with high particle concentration and Ohnesorge numbers (Oh) below 1. The fabrication process used two piezoelectric printheads to inject nanoceramic ink and nanosilver ink to create a ceramic substrate and a surface interdigital electrode (IDE). The substrate sintering shrinkage was 21.5 % and the surface IDE co-fired at the same shrinkage rate as the substrate thus ensuring all electrode pattern details. The electrode conductors demonstrated effective line widths of up to 0.21 mm. Microscopic characterisation of the interface between silver and substrate using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) confirmed the absence of significant elemental diffusion, and X-ray diffraction spectroscopy (XRD) results demonstrate that there is no second-phase generation, thus ensuring the effectiveness of the silver electrode. The ceramic substrates exhibit good thermal stability below 400 ℃ and have a coefficient of thermal expansion (∼ 4.1 ppm/℃) similar to that of silicon, indicating reliability in packaging. A microstrip patch antenna with the design frequency at 9–11 GHz was made through the same MJ procedure, which was experimentally measured to have a resonant frequency of 10.1 GHz, an S11 measurement of −24.6 dB, a simulated radiation efficiency of 88.01 %, and a high gain of up to 7.52 dB. Finally, a curved LTCC substrate with a radius of curvature of 50 mm and curved circuits was successfully fabricated using MJ technology. Interestingly, the curvature of the substrate maintained its original shape both before and after the sintering process, and the serpentine conductor pattern exhibited synchronous contraction, which implies the potential for developing a conformal LTCC utilizing MJ technology.

Facile Preparation of Monodisperse Cu@Ag Core-Shell Nanoparticles for Conductive Ink in Printing Electronics.

Copper-based nanoinks are emerging as promising low-cost alternatives to widely used silver nanoinks in electronic printing. However, the spontaneous oxidation of copper under ambient conditions poses significant challenges to its broader application. To address this issue, this paper presents an economical, large-scale, and environmentally friendly method for fabricating Cu@Ag nanoparticles (Cu@Ag NPs). The as-prepared nanoparticles exhibit a narrow size distribution of approximately 100 nm and can withstand ambient exposure for at least 60 days without significant oxidation. The Cu@Ag-based ink, with a 60 wt% loading, was screen-printed onto a flexible polyimide substrate and subsequently heat-treated at 290 °C for 15 minutes under a nitrogen atmosphere. The sintered pattern displayed a low electrical resistivity of 25.5 μΩ·cm (approximately 15 times the resistivity of bulk copper) along with excellent reliability and mechanical fatigue strength. The innovative Cu@Ag NPs fabrication method holds considerable potential for advancing large-scale applications of copper-based inks in flexible electronics.

Surface-to-Volume Ratio Affects the Toxicity of Nanoinks in Daphnids

The Organization for Economic Co-operation and Development (OECD) has set widely used guidelines that are used as a standardized approach for assessing toxicity in a number of species. Given that various studies use different experimental setups, it is difficult to compare findings across them as a result of the lack of a universally used setup in nano-ecotoxicology. For freshwater species, Daphnia magna, a commonly used filter feeding crustacean, can generate significant molecular information in response to pollutant exposure. One factor that has an effect in toxicity induced from nanomaterials in daphnids is the surface-to-volume ratio of the exposure vessels; however, there is limited information available about its impact on the observed effect of exposure. In this study, daphnids were exposed to silver nanoparticle ink in falcon tubes and Petri dishes for 24 h. Toxicity curves revealed differences in the observed mortality of daphnids, with animals exposed in Petri dishes displaying significantly higher mortality. Differences in the activities of a number of key enzymes involved in the catabolism of macromolecules and phosphate were also observed across the exposure setups, indicating possible differences in the toxicity mechanism of silver nano-ink. Understanding the impact of factors relevant to experimental setups in ecotoxicology can increase the reproducibility of testing, and also reduce experimental costs, time, generated waste, and daphnids used in research.

Printable Silver Nano Ink for Bendable Ultrawideband Antenna with Triple-Notch Characteristics

Flexible antennas based on the printed flexible electronic technology are of great interest for important applications in wireless communication systems due to their distinctive features over traditional rigid-based antennas. The ultrawideband (UWB), notch characteristics, and bending capabilities of such antennas are crucial for flexible and wearable applications. Currently, only a few are focused on the printed flexible electronics technology with printable ink materials for UWB antenna applications. In addition, flexible UWB antennas with triple-notch characteristics and good bending performance are rarely reported. Thus, there is a need to make advances in this area. Here, we describe the application of a printable silver nanoparticle-based ink for rapidly fabricating an antenna with bendable and triple-notch characteristics designed for UWB communication systems. The ink, composed of monodisperse silver nanoparticles, isopropanol, and ethyl glycol, can easily produce favorable conductive patterns at a sintering temperature below 130 °C after inkjet printing. The antenna is designed on a flexible polyethylene terephthalate (PET) substrate and has a moderate size of 27 mm × 38 mm × 0.12 mm. It operates at a frequency range of 1.9–10.75 GHz, which covers the desired UWB frequency band. By loading a “U”-like slot and two “C”-like slots on the radiating patch, band rejections were generated at 3.2–3.8, 5.3–6.2, and 7.8–8.5 GHz, shielding the interference from world interoperability for microwave access, wireless local area networks, and X uplink bands. The bending results show that the antenna retains good UWB and triple-notch performance even after bending along the Y- or X-axis for different degrees. An antenna prototype was finally fabricated by inkjet printing of the silver nano ink on the PET substrate, exhibiting the desired notch characteristics and excellent bendability. The fabricated antenna prototype proved the feasibility of use as a flexible device at an ultrawide frequency band. The research provides a design guide for flexible antennas with notch features toward flexible and wearable electronics.

Production of Silver Nano-Inks and Surface Coatings for Anti-Microbial Food Packaging and Its Ecological Impact

Food spoilage is an ongoing global issue that contributes to rising carbon dioxide emissions and increased demand for food processing. This work developed anti-bacterial coatings utilising inkjet printing of silver nano-inks onto food-grade polymer packaging, with the potential to enhance food safety and reduce food spoilage. Silver nano-inks were synthesised via laser ablation synthesis in solution (LaSiS) and ultrasound pyrolysis (USP). The silver nanoparticles (AgNPs) produced using LaSiS and USP were characterised using transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, UV-Vis spectrophotometry and dynamic light scattering (DLS) analysis. The laser ablation technique, operated under recirculation mode, produced nanoparticles with a small size distribution with an average diameter ranging from 7-30 nm. Silver nano-ink was synthesised by blending isopropanol with nanoparticles dispersed in deionised water. The silver nano-inks were printed on plasma-cleaned cyclo-olefin polymer. Irrespective of the production methods, all silver nanoparticles exhibited strong antibacterial activity against E. coli with a zone of inhibition exceeding 6 mm. Furthermore, silver nano-inks printed cyclo-olefin polymer reduced the bacterial cell population from 1235 (±45) × 106 cell/mL to 960 (±110) × 106 cell/mL. The bactericidal performance of silver-coated polymer was comparable to that of the penicillin-coated polymer, wherein a reduction in bacterial population from 1235 (±45) × 106 cell/mL to 830 (±70) × 106 cell/mL was observed. Finally, the ecotoxicity of the silver nano-ink printed cyclo-olefin polymer was tested with daphniids, a species of water flea, to simulate the release of coated packaging into a freshwater environment.

Inkjet-printed plasma-functionalized polymer-based capacitive sensor for PAHs

The inkjet-printing technology is utilized to foster conducting layers, interconnections, and other features on different substrates of which its success greatly depends on the surface properties of the substrates. In the present work, we reported the use of low-temperature plasma (LTP) to assist in tailoring the surface properties of polyethylene terephthalate (PET). This facilitated the inkjet printing of a capacitive electrode sensor design using silver nano-ink (AgNI) for polycyclic aromatic hydrocarbons (PAHs). PAHs are ubiquitous environmental pollutants that are of great health concern. We have sifted methyl methacrylate (MMA), N-vinylpyrrolidone (VP), and oxygen (O2) as plasma fed-gases for improving the adhesion of printed AgNI on PET. We observed improved surface hydrophilicity of the plasma-treated PET (p-PET). This was evidenced by the decrease in water contact angle (WCA). The change in surface chemistry with plasma treatment was assessed using X-ray Photoelectron spectroscopy (XPS). Atomic Force Microscopy (AFM) was employed in determining the nanoscale surface roughness of PET. We then fabricated the capacitive sensor using AgNI to quantitatively sense the PAH from aqueous media. This sensor was subsequently characterized using Scanning Electron Microscopy (SEM) and Keyence 3D imaging. The capacitance values have shown a linear response with increased PAH concentration. The sensor design exhibits a high sensitivity for PAH concentrations up to 0.05 ng/mL. Ultimately, these results have demonstrated the potential of this polymer device for pollutant sensing applications.

Solderability and Reliability of Sintered Nano-Ag Bond Pads of Printed Re-Distribution Layer

Abstract Redistribution layer (RDL) is one key enabling technology for advanced packaging. RDL is usually fabricated at wafer level by a photolithography process. An alternative approach for implementing RDL by additive manufacturing (AM) method is proposed in this study. This allows RDL to be fabricated on a singulated chip. Nanosilver (nano-Ag) ink is printed on the silicon chip to form routing traces and bond pads. However, the Ag pad may be consumed by the solder quickly if the reflow process is not properly controlled. The mechanical integrity of the solder joint was evaluated by both solder ball shear and die shear tests. A high temperature storage test and humidity test were carried out to evaluate the solder joint reliability. Experiment results showed that the Ag pad fabricated by AM is compatible with surface mount technology (SMT). Reliable solder joints on the Ag pad were achieved. There was no significant change in the Ag3Sn intermetallic compound (IMC) layer thickness and mechanical strength after aging at high temperature and high humidity conditions. There was no early solder joint failure observed. The finding of the present study will serve as a very useful reference for the future practice of forming solder joints on sintered nano-Ag pads.

High Operation Frequency and Strain Tolerance of Fully Printed Oxide Thin Film Transistors and Circuits on PET Substrates.

The major limitations of solution-processed oxide electronics include high process temperatures and the absence of necessary strain tolerance that would be essential for flexible electronic applications. Here, a combination of low temperature (<100°C) curable indium oxide nanoparticle ink and a conductive silver nanoink, which are used to fabricate fully-printed narrow-channel thin film transistors (TFTs) on polyethylene terephthalate (PET) substrates, is proposed. The metal ink is printed onto the In2 O3 nanoparticulate channel to narrow the effective channel lengths down to the thickness of the In2 O3 layer and thereby obtain near-vertical transport across the semiconductor layer. The TFTs thus prepared show On/Off ratio ≈106 and simultaneous maximum current density of 172 µA µm-1 . Next, the depletion-load inverters fabricated on PET substrates demonstrate signal gain >200 and operation frequency >300kHz at low operation voltage of VDD = 2V. In addition, the near-vertical transport across the semiconductor layer is found to be largely strain tolerant with insignificant change in the TFT and inverter performance observed under bending fatigue tests performed down to a bending radius of 1.5mm, which translates to a strain value of 5%. The devices are also found to be robust against atmospheric exposure when remeasured after a month.

Hansen Solubility Parameter Analysis on Dispersion of Oleylamine-Capped Silver Nanoinks and their Sintered Film Morphology.

Optimizing stabilizers and solvents is crucial for obtaining highly dispersed nanoparticle inks. Generally, nonpolar (hydrophobic) ligand-stabilized nanoparticles show superior dispersibility in nonpolar solvents, whereas polar ligand (hydrophilic)-stabilized nanoparticles exhibit high dispersibility in polar solvents. However, these properties are too qualitative to select optimum stabilizers and solvents for stable nanoparticle inks, and researchers often rely on their experiences. This study presents a Hansen solubility parameter (HSP)-based analysis of the dispersibility of oleylamine-capped silver nanoparticle (OAm-Ag NP) inks for optimizing ink preparation. We determined the HSP sphere of the OAm-Ag NPs, defined as the center coordinate, and the interaction radius in 3D HSP space. The solvent’s HSP inside the HSP sphere causes high dispersibility of the OAm-Ag NPs in the solvent. In contrast, the HSPs outside the sphere resulted in low dispersibility in the solvent. Thus, we can quantitatively predict the dispersibility of the OAm-Ag NPs in a given solvent using the HSP approach. Moreover, the HSP sphere method can establish a correlation between the dispersibility of the particles in inks and the sintered film morphology, facilitating electronic application of the nanoparticle inks. The HSP method is also helpful for optimizing stabilizers and solvents for stable nanoparticle inks in printed electronics.

Influence of process parameters on the characteristics of electrohydrodynamic-printed UV-curing conductive lines on the fabric

As a similar technology to the near-field static electrospinning, the emerging electrohydrodynamic (EHD) printing technology with digital printing process and compatibility of viscous particle-blended inks is one of the simplest methods of fabricating multifunctional electronic textiles. With increasing demands for textile-based conductive lines with controllable width and excellent electrical performance, it is of great importance to know the influence of key process parameters on the morphology and electrical properties of EHD-printed UV-curing conductive lines on the fabric. This work will systematically explore the effect of the EHD printing process parameters (i.e. applied voltage, direct-writing height, flow rate and moving velocity of the substrate) on the morphology and electrical performance of the EHD-printed textile-based conductive lines, especially focus on the diffusion and penetration of inks on the rough and porous fabric. The UV-curing nano-silver ink with low temperature and fast curing features was selected, and the line width and electrical resistance of printed lines under different process parameters were observed and measured. The results showed that, unlike previous results about EHD printing on smooth and impermeable substrates, the ink diffusion related to fabric textures had a greater effect on the fabric-based conductive line width than the applied voltage and direct-writing height in the case of a stable jet. Meanwhile, the relationship between the line width and the flow rate met the equation of , and the minimum volume on fabric per millimeter was 0.67 μl to form continuous line with low electrical resistance. Additionally, the higher substrate moving velocity resulted in a smaller line width, while it deteriorated the thickness uniformity and electrical property of printed lines. Generally, due to the effect of surface structure of the fabric on the spreading and penetrating behavior of inks, the flow rate and the substrate moving velocity are two significant parameters ensuring the electrical property of printed lines. It is believed that these findings will provide some guides for applying EHD printing technology into flexible electronics on the woven fabric.

Rational design and evaluation of UV curable nano-silver ink applied in highly conductive textile-based electrodes and flexible silver-zinc batteries

• A novel UV curable nano-silver ink with low-temperature and short-time curing features was developed for the application of high-performance e-textiles. • By investigating the influence of ink composition, it can provide a guideline to the ink formulation design and understand the mechanism of printing defect formation. • The electrical conductivity of textile-based electrode was achieved as high as 2.47 × 106 S/m when the nano-silver content of conductive ink was 60 wt%. • The textile-based electrode showed outstanding mechanical durability and could maintain resistance stability within 10 washing and drying cycles. • The application potential of conductive ink in fabricating e-textiles was confirmed by using the textile-based electrode as the cathode of silver-zinc battery. 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 × 10 6 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.