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Attention has recently been paid to ink-jet printing inks to more environmentally friendly types and faster methods with lower energy consumption. The ink-jet printing industry has a preference to use ultraviolet-curable inks for packaging and labeling applications. This research reports a simple approach to prepare a water-based UV-curable ink-jet ink based on urethane acrylate to print onto the transparent flexible polyethylene terephthalate substrate. Isophorone diisocyanate, dimethylolpropionic acid, a low molecular weight polyester resin, and 2-hydroxyethyl methacrylate used to synthesize the urethane acrylate resin. Then, the prepared resin was neutralized with triethylamine and emulsified in deionized water. Fourier transformed infrared spectroscopy spectra characterized the chemical structure of synthesized resin. The gel permeation chromatography was used to determine the synthesized resin's molecular weight. The hydroxyl value, acid value, conversion percentage under UV radiation, transparency, haze, and surface tension results of the emulsified resin were measured. The physical properties of prepared ink-jet ink, such as rheology, surface tension, and dynamic light scattering, were measured. The ink-jet ink could fabricate uniform patterns by a general ink-jet printer onto the transparent polyethylene terephthalate flexible substrate. Eventually, the acceptable appearance was achieved due to the transparency and clarity of the printed polyethylene terephthalate. [ABSTRACT FROM AUTHOR]

Metal halide perovskites have raised huge excitement in the field of emerging photovoltaic technologies. The possibility of fabricating perovskite solar cells (PSCs) on lightweight, flexible substrates, with facile processing methods, provides very attractive commercial possibilities. Nevertheless, efficiency values for flexible devices reported in the literature typically fall short in comparison to rigid, glass‐based architectures. Here, a solution‐processable fullerene derivative, [6,6]‐phenyl‐C61 butyric acid n‐hexyl ester (PCBC6), is reported as a highly efficient alternative to the commonly used n‐type materials in perovskite solar cells. The cells with the PCBC6 layer deliver a power conversion efficiency of 18.4%, fabricated on a polymer foil, with an active area of 1 cm2. Compared to the phenyl‐C61‐butyric acid methyl ester benchmark, significantly enhanced photovoltaic performance is obtained, which is primarily attributed to the improved layer morphology. It results in a better charge extraction and reduced nonradiative recombination at the perovskite/electron transporting material interface. Solution‐processed PCBC6 films are uniform, smooth and displayed conformal capping of perovskite layer. Additionally, a scalable processing of PCBC6 layers is demonstrated with an ink‐jet printing technique, producing flexible PSCs with efficiencies exceeding 17%, which highlights the prospects of using this material in an industrial process. [ABSTRACT FROM AUTHOR]

The dispersion of low surface polarity ultra-fine powders has been a technical bottle-neck in many industrial applications, including ceramic or glass decoration and solar electrodes. Herein, we report a surface modification method to improve the adsorption strength between the ultra-fine (300 nm) powder and dispersant by coating a layer of mesoporous silica on the surface of a glass frit. The modified ultra-fine glass frit shows a high density of polar surface functional groups which can increase the adsorption amount and strength between the modified powder and the dispersant, as confirmed by the adsorption experiment and IR analysis. The modified powder also was used to prepare ceramic ink which can be completely filtered under a 1 μm sized pores filter, thus satisfying the requirement of industrial ink-jet printing. [ABSTRACT FROM AUTHOR]

The Department of Defense (DOD) and first responder communities are evaluating and developing optical systems for the detection and identification of explosives and components used for assembling homemade explosives (HMEs). Emerging detection technologies must be evaluated with authentic hazard material concentrations to ensure their accurate and reliable use in the field. In this work, infrared (IR) reflectance spectra over the spectral rage of 1000-1700 cm-1 were collected for different concentrations of inkjet-printed RDX (cyclotrimethylenetrinitramine) samples deposited onto aluminum substrates. A plot of the integrated area of both the symmetric and asymmetric NO2 vibrational bands for RDX on aluminum exhibited good linearity over the concentration range 20-500 µg/cm². Detection limits for RDX on an aluminum surface were calculated to be 10.7 µg/cm² for the symmetric NO2 vibrational band and 1.4 µg/cm² for the asymmetric NO2 vibrational band. Evaluation of the NO2 vibrational band areas at different locations of the RDX array demonstrated that the samples exhibited good homogeneity across the surface. The concentration of an unknown sample of RDX on aluminum was determined using the fitted equations; results showed good agreement between the calculated and actual RDX surface concentration. The lot-to-lot variation of RDX on the aluminum surface was compared using the long wavelength infrared (LWIR) spectral band areas for two different lots of standards printed at the same RDX surface concentration. Results showed excellent lot-to-lot agreement indicating good reproducibility of the standards for RDX. [ABSTRACT FROM AUTHOR]

Bioresorbable polymer microparticles are widely used to provide long-lasting drug delivery in several chronic diseases. Having fine control over the physical properties of such microparticles can improve product reproducibility, performance and process efficiency. By using an ink-jet based droplet generator device, a new approach to microparticle manufacture was explored that uses an extremely rapid phase-separation to produce highly uniform, injectable microparticles from PLGA and a PLA/PLGA blend. To demonstrate the possible pharmaceutical applicability of the microparticle printing technique, the approved peptides ciclosporin A and octreotide were formulated, producing low-density microparticles that showed between sustained release over several months. The facile scale-up of the technique was demonstrated by using an array of 256 ink-jet nozzles, allowing over 1 million discrete particles per second to be produced. The new apparatus and methods described herein could be used across a wide range of biomaterials and therapeutic compounds. [ABSTRACT FROM AUTHOR]

Roll-to-roll (R2R) solution processing of thin film devices offers savings to cost, time, and material waste. Emerging technologies in electronics, optoelectronics, and microfluidics could potentially benefit from these manufacturing advantages. However, the associated complex pattern requirements are difficult to attain with traditional solution-based methods, barring significant concessions to device performance and process scalability. In this paper, we present and implement a novel hybridization of continuous ( e.g ., slot die) and on-demand ( e.g ., inkjet) techniques designed to address these shortcomings, wherein outflow from localized regions of an extrusion die is actuated in real time to produce patterns. Pattern features were produced with aqueous solutions of poly(vinyl alcohol) (PVA), and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), and deposition phenomena were observed in situ using a specialized roll feed imaging system. Minimum feature size is shown to be directionally dependent, with transient flow effects dominating along the axis coincident with substrate motion, and sensitive to several process inputs as well as coating material properties. Strategies for managing residual fluid in the die cavity and beneath the die lip are illustrated, through flow actuation mechanisms and exploitation of deposition phenomena, to optimize pattern fidelity. [ABSTRACT FROM AUTHOR]

The ink-jet printing has been widely applied in the decoration of ceramic tiles in last ten years since its excited characteristics provide the possibility to produce the customized ceramic tiles with higher image definition at a lower cost in a shorter duration. The number of ink-jet printers in operation worldwide increased rapidly in recent years. Besides the printer, one of the critical factors for an effective printing is inks. This paper focuses on the ceramic ink and reviews recent development on the preparation of ceramic inks by various methods, such as sol–gel, reverse microemulsion, polyol, hydrothermal and mechanical grinding. Some aspects for future development are proposed based on the application of ceramic inks in industries. [ABSTRACT FROM AUTHOR]

In this study, the cotton fabrics were modified with different polyamidoamine (PAMAM) dendrimer concentrations to yield antimicrobial and efficient polymeric materials for ink-jet printing. PAMAM dendrimer has been covalently grafted on cotton fabric via the reaction of cellulosate anion with the cynuric chloride. The obtained modified cotton fabrics were characterized by FTIR and TGA. The morphology and yellowness of modified cotton fabrics were analysed by SEM and UV spectroscopy. The ink-jet printing onto modified cotton fabrics were evaluated at different pHs. The results at optimum pH indicated that by increasing the PAMAM dendrimer concentration in modified cotton fabric not only the colour strength of reactive ink-jet printed fabric increased but also the antimicrobial cotton fabric produced. A comparision between printing modified and unmodified cottons suggest that the PAMAM dendrimer has the potential for using in single-phase ink-jet printing. The yielded prints demonstrate excellent colour fastness for washing and dry/wet crocking properties. [ABSTRACT FROM AUTHOR]

Highlights: [•] Clear evidence that temperature could be used to manipulate the wetting properties. [•] Usability studies of organic solar cell materials never investigated previously. [•] Implementation of ZnO nanorod layers, which are a very promising materials for various applications. [•] Proof those elevated temperatures permanently reverse the effects of plasma treatment. [Copyright &y& Elsevier]

Abstract: Cellulose linen fabric samples subjected to cationization using different cationizing agents: dodecyl trimethyl ammonium bromide (DTAB), tetra methyl ammonium hydroxide (TMAH), and Quat-188, via pad batch technique, followed by ink jet printing with reactive dyes. The %N as well as the K/S of the cationized samples was found to be depends on: (a) the nature of the cationizing agent and (b) on the time of batching. As the latter increases both of the nitrogen content and K/S increases to a maximum depending on the nature of the reagent used. Further increase in the batching time up to 30h is accompanied by a decrease in both the %N and K/S irrespective of the nature of the cationizing agent used. Cationization improves the printability of reactive dye ink jet printed linen fabrics with no remarkable effect on the overall color fastness properties. [Copyright &y& Elsevier]

UV-curable inks based on a poly(ethylene glycol) diacrylate (PEGDA) matrix and containing a dispersion of aqueous Ag nanoparticles in different amounts from 10 to 50% are prepared for the fabrication of inkjet printed resistors. The composition is adapted to the inkjet requirements in terms of viscosity, surface tension, and particle size. The gel content, glass transition temperature, conversion, UV-Vis absorption, morphology, and DC electrical properties of the materials are characterized. It is found that the NPs dispersed in the polymeric matrix realize a percolating path by aligning themselves in chains, which results in a reduction of the percolation threshold. Thus, resistivity is well beyond the dissipative range. [ABSTRACT FROM AUTHOR]

An eddy current sensor with an ink-jet printed flexible inductor has been designed and fabricated. The inductor has been designed by means of software developed in-house. It has been fabricated by ink-jet printing with silver ink on a flexible substrate. The inductor is a part of the oscillator circuit whose oscillating frequency is measured by a microcontroller. The sensor characteristics have been analyzed for two types of application. The first considered application is the displacement of a large conductive target in a direction perpendicular to the inductor plane. The second considered application is the displacement of a small steel ball parallel to the inductor plane. Inductance and oscillating frequency have been measured in order to completely characterize the sensor. The obtained results validate the use of the sensor for both considered applications, and are in good agreement with the simulations. The advantages of this type of sensor are low cost, the possibility for the inductor to match any curved surface and flexibility and precision of the inductor design. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we propose a piezoelectric droplet generator for injection of well-defined amounts of sample in capillary electrophoresis. We demonstrate stable, precise and drop-on-demand droplet formation for various solutions, with precise control of waveform driving piezoelectric crystal inside the ink-jet head. By tuning the waveform, we can also manipulate the droplet size and delivery frequency. This injector was used in sampling for capillary electrophoresis. As a state-of-the-art application, the analysis of theobromine, caffeine and theophiline using micellar electrokinetic chromatography was developed. The volume of sample (single droplet) analyzed in this experiment was 179pL (RSD=1.2%, n=10). The detection limits for caffeine, theobromine, and theophiline are 0.02, 0.08 and 0.06mML−1, respectively. Compared with conventional methods, the combination of picoliter droplet dispenser with capillary electrophoresis allows precise and accurate sampling, as well as for reduced sample consumption, which will prove to be an efficient tool in quantitative separation and analysis. [Copyright &y& Elsevier]

Abstract: In this work, an automatic multi-channel ink-jet for chemiluminescence (CL) analysis was developed. The four-channel ink-jet device was controlled by a home-made circuit. Differing from the classic flow injection CL, the whole procedure for CL analysis was automatically completed on a hydrophobic glass side. CL reaction of luminal and hydrogen peroxide for the determination of horseradish peroxidase (HRP) was selected as an application to automatic CL analysis platform. All solutions delivered by different channels were precisely ejected to the same position of the glass slide for the CL analysis. The consumption of reaction solution was reduced to nanoliter level. The whole CL analysis could be completed in less than 4min, which was benefited from the prompt solution mixing in small size of droplet. The CL intensity increased linearly with HRP concentration in the range from 0.01 to 0.5μgmL−1. The limit of detection (LOD) (S/N=3) was 0.005μgmL−1. Finally, the automatic CL system could also be used for the detection of HRP in HRP–protein conjugates, which showed its practical application in immunoassay. [Copyright &y& Elsevier]

Design considerations for ultraviolet-nanoimprint lithography resists were investigated focusing on the major issues of ink-jetting performance, pattern formability, release property, and dry etching resistance. Regarding ink-jetting performance, small droplet ink-jetting of 0.7 pl was successfully demonstrated by adjusting the resist fluid property to the ink-jet coater and controlling the resist volatilization. Regarding pattern formability, a resist pattern was imprinted from a mold pattern of 28 nm in width and 60 nm in depth without pattern dimension change. It was thought that modulus control of the resist was more important than resist shrinkage in achieving excellent pattern formability. As for release property, resist with fluorine monomer and with nonreactive fluorine antisticking agent were compared. The results indicated that resist design has the capability to both reduce separation force and maintain a clear mold surface. The mold release agent decomposed with an increasing number of imprint shots, but the low release-force resist with nonreactive antisticking agent was able to control degradation of the mold release agent and thus improve release property endurance. Regarding etching resistance, it was found that increasing the ring parameter of resist is essential for high etching resistance, and resulted in improved etched pattern features of the substrate. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, three-dimensional ordered microbeads structure (3 DOS) was controllably constructed, and was firstly adopted in the enzyme-linked immunosorbent assay (ELISA) for the detection of IgA. The 3 DOS analytical matrix greatly increased the reaction surface and improved the sensitivity of ELISA microassay. Briefly, the 3 DOS dot microarray for bio-analysis was dispensed by the ink-jet micro-device, and assembled in a close box with controlled relative humility (RH). The influence of supporting substrate material, concentration of microbeads suspension, and RH on the conformation of 3 DOS was also discussed in detail. Then the optimum conditions for the uniform and stable 3 DOS for microassay were achieved, and the uniform and stable 3 DOS microarray for the enzyme-linked immunosorbent assay (ELISA) was built up. Finally, the ELISA microassay on the 3 DOS microarray was done to detect IgA and compared with the classic 96-well plate and blank PDMS surface. The results have shown that 15 times reaction time was shortened due to the decreasing of the mass transferring distance; Almost 10 times sensitivity was obtained owing to the increased reaction surface; the large dynamic range was achieved in the 3 DOS ELISA microarray. [Copyright &y& Elsevier]

Abstract: An ink-jet printing method was proposed to solve several conventional problems of ink jet process. PVK (poly(9-vinylcarbazole)) thin film was synthesized and simultaneousely patterned by the reactive ink-jet process (RIP). Gel permeation chromatography shows a linear relationship between the molecular weight of the PVK and the reaction time. The as-synthesized PVK with a controlled molecular weight was applied to an OLED device. Most of the OLED with the RIP–PVK film performed better compared to the reference OLEDs. The luminance graphs indicated the existence of a proper molecular weight leading to the optimum structural conformity which was matched well to the modified OLED structure, showing a linear relationship with the reaction time in the turn-on threshold. This result implies that one can control the proper molecular weight of a polymer and thus the electrical properties of an OLED device via the RIP method. [Copyright &y& Elsevier]

Ink-jet deposition enables more efficient, economic, scalable manufacturing for a wide variety of materials than other additive techniques. The impact of droplets onto a substrate is critical for accuracy control and optimisation of the droplet deposition process. However, most previous research about droplet impact focused on the spreading radius of the droplet, which does not provide enough information for manufacturing purposes. This paper presents a new measure of droplet shape characterisation so that the droplet deposition process can be optimised to build desired geometries. A dimensional analysis is conducted to reduce the number of parameters of the impact conditions. Then the shape evolution of a wide range of impact conditions is simulated with a validated numerical model. The effects of the dimensionless numbers on the shape evolution are examined and analysed. Successive multiple droplets impact is also investigated. [ABSTRACT FROM PUBLISHER]

Abstract: Hyperbranched polyurethane-methacrylates were synthesized and used as oligomers for ink-jet printing of LCD color filters. Pigment-based inks containing these hyperbranched polymers (HBPs) were ink-jet printed and fixed by a UV curing reaction to make color patterns on glass substrates. The HBPs exhibited excellent compatibility with pigments and other UV-curable compositions in inks. Surfactants were added and hyperbranched polymers were changed to adjust the rheology of the inks; this adjustment improved the ink for ink-jet printing, with regard to performance such as straight jetting trajectory, deposition accuracy, and uniform drop size. The UV-cured patterns that incorporated HBPs as ink components exhibited good chemical resistance and high nanoindentation hardness. [Copyright &y& Elsevier]

Abstract: An ink-jet method for fabrication of fine and smooth front side highly conductive silver lines on crystalline Silicon substrate is described. The fabricated conductive silver lines on different substrates are characterized by means optical microscope, optical profilometers, scanning electron microscope (SEM), and electrical measurements. The coffee-ring effect is controlled by increasing the solid loading of the ink from 20W% to 40W% and printing at optimum substrate temperature (90–100°C) and optimum printing parameters. Smooth printed conductive silver lines, with line thickness ranges from 0.8∼0.9μm for single pass, are obtained. When increased substrate temperature, a significant reduction of spreading of ink was observed. And conductive silver lines obtained at optimum substrate temperature (90–100°C), free of periodic wrinkles and line bleeding, are produced. The influence of annealing temperature on line resistance, the morphology and functionality of the printed conductive silver lines is optically and electrically analyzed. To deposit thicker lines multiple passes of ink-jet printing were done on polished single crystalline silicon (sc-Si) and standard alkaline (NaOH) textured n+/p single crystalline silicon (n+/p sc-Si). Moreover, the printed conductive silver lines are characterized optically and electrically. And, promising results in terms of printed line thickness and electrical property are achieved. [Copyright &y& Elsevier]

Abstract: An all-printed photosensor based on polyfluorene derivatives has been developed for high illuminance range detection (>100klux). The active layer is a blend of hole-accepting poly(9,9′-dioctylfluorene-co-bis-N,N′-(4-butylphenyl)-bis-N,N′-phenyl-1,4-phenylenediamine) (PFB) and electron-accepting poly(9,9′-dioctylfluorene-co-benzothiadiazole) (F8BT). A top-absorbing architecture was used with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the transparent electrode. The surface energy of the PEDOT:PSS ink was modified in order to allow printing directly onto the hydrophobic surface of the PFB:F8BT blend layer, placing the transparent electrode at the top of the light sensor structure. The all-printed photosensor shows a linear response over multiple measurements within the illuminance range of (100–400) klux. [Copyright &y& Elsevier]

Abstract: We report a rapid patterning method for interconnects fabrication combining the ink-jet printing of silver nanoparticles and laser sintering on the ceramic substrate. The optimal parameters of laser irradiation were found. As-fabricated interconnects on ceramic substrate possess a sheet resistance 0.38Ω/sq and have good adhesion to substrate. Also, the pulsed laser annealing of silver particles after drying on polyimide substrate was investigated, and optimal parameters of laser irradiation were found to form peeling-free structures. The conductivity of as-prepared lines reached about 20% of bulk silver. [ABSTRACT FROM AUTHOR]

Abstract: Organic thin film transistors with channel lengths below 20μm have been fabricated on plastic substrates using a combination of rotogravure and ink-jet printing exclusively. Gravure is utilized to deposit thin, smooth, and narrow metal lines ideal for gate electrodes; a poly(4-vinylphenol) dielectric; and a poly(2,5-bis(3-tetradecylthiophene-2-yl)thieno[3,2-b]thiophene) (pBTTT) semiconductor using a heated roll. A novel fluid guiding technique is used to maintain closely spaced ink-jet printed source and drain (S/D) contacts. Together these printing processes yield aggressively scaled yet easily manufacturable TFTs with operating frequencies of 18kHz. [ABSTRACT FROM AUTHOR]

Abstract: A technique for the fabrication of chemiresistive sensors using ink-jet printing is reported. Gold nanoparticles stabilised in water were ink-jet printed on gold interdigitated electrodes patterned on an oxidized silicon wafer. As a first step the influence of substrate functionalization, electrode spacing, and nanoparticle density were investigated by electrical measurements and microscopy imaging. Finally a second layer of PHEMA polymer was printed on top of the gold nanoparticle films. The device was exposed to vapours of humidity and ethanol and the obtained results are presented. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we presented a novel water-based nanoparticle printing ink which can easily be used in producing electric-conductive patterns for the microfabrication and microelectronic devices by commercial printers. The well-dispersed nanoparticle ink was composed of metallic colloids which had a gold core less than 5nm in diameter and were protected by two overlapped layers of polymers, poly(N-vinylpyrrolidone) (PVP) and acrylic resin (AR). The double layer protected gold nanoparticle (AuNP) ink was stable against aggregation for more than 1 year even at gold concentration higher than 20%. Viscosity of as-prepared ink was similar to the commercial inks which could be used in producing continuous and smooth lines 10μm in width and could be printed on various substrates. It has been found that the obtained gold patterns after sintered at 500°C for 3h would convert to electrical conductive ones. The density of metallic particles as well as the conductivity of patterns can be controlled by mediating the number of printing layers and the conditions of sintering process. A 50-layer printed line obtained in our experiment showed apparent conductivity of 8.0×104 Scm−1 which was near to the conductivity value of the bulk gold metal. [Copyright &y& Elsevier]

The ink-jet printing method is an important process in display industry due to the low-cost production of large-scale electronic devices. In this work, we prepared the nanoparticle indium tin oxide (ITO) solutions for ink-jet printing and characterized the electrical, structural and morphological properties of the film. The improvement of conductivity after reduction process was correlated with the sharpening of the diffraction peak as proved by X-ray diffraction measurement. The ITO inks was coated on a glass by spin-coating process and patterned by the ink-jet printing technique using a 50 μm diameter ink-jet nozzle. The sheet resistance and optical transmission of ITO thin film was ca. 50∼300Ω/sq and ca. 75∼95%, respectively. The electrical resistance of patterned ITO lines showed about 5∼30 * 103Ω. The detailed relationship between microstructure and properties are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Here we report on ink-jet manufactured chemical sensors based on polymer-carbon black composites. Both sensing elements and electrical contacts have been made by ink-jet on alumina substrates. Filler dispersions, films morphology, electrical properties and time stability of devices have been investigated. Sensors have been tested at increasing acetone and toluene concentrations in air at room temperature. Their behaviour is compared to devices whose electric contacts have been made by a photolithographic process and the sensing film deposited by casting or ink-jet. [Copyright &y& Elsevier]

Abstract: Novel materials and a metallization technique for the printed electronics were studied. Insulator inks and conductive inks were investigated. For the conductive ink, the nano-sized copper particles were used as metallic sources. These particles were prepared from a copper complex by a laser irradiation process in the liquid phase. Nano-sized copper particles were consisted of a thin copper oxide layer and a metal copper core wrapped by the layer. The conductive ink showed good ink-jettability. In order to metallize the printed trace of the conductive ink on a substrate, the atomic hydrogen treatment was carried out. Atomic hydrogen was generated on a heated tungsten wire and carried on the substrate. The temperature of the substrate was up to 60°C during the treatment. After the treatment, the conductivity of a copper trace was 3μΩcm. It was considered that printed wiring boards can be easily fabricated by employing the above materials. [Copyright &y& Elsevier]

Abstract: Direct fabrication of ceria film and patterns were conducted by an ink-jet deposition method where a precursor solution was jetted towards a heated substrate (≤300 °C) according to the required pattern without any post heat treatments. X-ray diffraction and Raman spectroscopic analyses revealed that the formed phases were crystallized CeO2 without any impurity phases and consisted of nanosized crystallites of <10 nm. The thicknesses were several hundred nanometers and the width of the patterns was about 350 µm. The film was dense and showed a high optical transparency in the visible region(>90%). Scanning electron microscopic analysis revealed that thin film patterns were free of cracks and all the films showed good adherence to the substrate. [Copyright &y& Elsevier]

Radio frequency identification (RFID) antennas for HF and UHF frequencies are ink-jet printed using commercially available silver nanoparticle ink. Quality factors of 5.3 and 9.4 are obtained for coil antennas targeted for 13.56 MHz when the printing and sintering process is repeated two and three times, respectively. The measured maximum effective aperture of the printed UHF antenna is only some decibels lower than that of an equivalent etched copper antenna and the maximum reading distance with 0.5 W (ERP) transmitted power is 3 m for continuous reading. These results suggest that obtaining a low enough series resistance for printed coils is challenging while printed RFID antennas for UHF do not set as strict requirements on conductivity. With a perfectly optimized structure, a UHF tag antenna printed in just one layer of ink can be practically equal in performance with the traditional etched copper and aluminum tags. [ABSTRACT FROM AUTHOR]

Chronic infection as a result of bacterial biofilm formation on implanted medical devices is a major global healthcare problem requiring new biocompatible, biofilm-resistant materials. Here we demonstrate how bespoke devices can be manufactured through ink-jet-based 3D printing using bacterial biofilm inhibiting formulations without the need for eluting antibiotics or coatings. Candidate monomers were formulated and their processability and reliability demonstrated. Formulations for in vivo evaluation of the 3D printed structures were selected on the basis of their in vitro bacterial biofilm inhibitory properties and lack of mammalian cell cytotoxicity. In vivo in a mouse implant infection model, Pseudomonas aeruginosa biofilm formation on poly-TCDMDA was reduced by ∼99% when compared with medical grade silicone. Whole mouse bioluminescence imaging and tissue immunohistochemistry revealed the ability of the printed device to modulate host immune responses as well as preventing biofilm formation on the device and infection of the surrounding tissues. Since 3D printing can be used to manufacture devices for both prototyping and clinical use, the versatility of ink-jet based 3D-printing to create personalised functional medical devices is demonstrated by the biofilm resistance of both a finger joint prosthetic and a prostatic stent printed in poly-TCDMDA towards P. aeruginosa and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Abstract: We present two novel methods for the preparation of arbitrary microscale patterns of polymers on surfaces with pre-defined topography. While photosensitive polymers are used commonly together with optical lithography, the methods presented can be used for non-photostructurable polymers and where spin-coating cannot be performed. As demonstrator of the viability of the proposed fabrication process, they have been applied for the definition of hydrophobic barriers on a microfluidics network, which is dedicated to selectively dispense liquid to a spotting device consisting of 12 silicon microcantilevers. [Copyright &y& Elsevier]

Abstract: Ink-jet printing has the advantage of easy formation of micro-patterns on rigid as well as flexible surfaces without needing conventional lithographic processes. By means of printing in selected areas, diamond seeding in designed patterns and areas is achieved. Properly designed ink with a desirable composition helps the formation of patterned structures with tailored functions. Ink containing nano-diamond particles was designed and used to print micro-structures, which were applied for further CVD growth of diamond by means of microwave plasma CVD. Promising applications of this technique are discussed. [Copyright &y& Elsevier]

Abstract: Ink-jet printing of metal nanoparticles is an attractive method for direct patterning conductive metal lines owing to low-cost, low-waste, and simple process. While most of the researches here focused on novel metals such as gold and silver, we have developed a conductive ink containing copper nanoparticles as an alternative that is inexpensive conductive material. Copper particles with a size of 40–50 nm were synthesized by polyol process, from which the well-dispersed conductive ink with low viscosity was prepared. We have successfully demonstrated a direct writing of the conductive lines using Cu conductive ink. The ink-jet printed copper patterns exhibited metal-like appearance and became highly conductive upon heat treatments. The resistivity of the film reached to 17.2 μΩ cm at 325 °C for 1 h in vacuum. [Copyright &y& Elsevier]

Abstract: We have employed ink-jet reaction method for direct fabrication of calcium tungstate patterns with the minimum width of around 150μm on cellulose based organic substrates without any post-firing and/or sintering. The XRD patterns revealed that the formed phase was a well-crystallized single phase of CaWO4 without any other impurity phases and the crystallite size was about 20±4nm. The Raman spectra were further confirmed the fabricated patterns consisted of CaWO4. The adhesion of CaWO4 to the substrate was good and revealed by SEM observations. The patterned CaWO4 showed the original blue luminescence when exposed to ultraviolet radiation (wavelength 254nm) under dark room conditions at room temperature. [Copyright &y& Elsevier]

We studied the thermal behavior of direct-printed conductive lines of Ag nanoparticles that were sintered at various times and temperatures. Transmission electron microscopy and an optical profiler were used to analyze the effect of sintering temperature and time on the shape and microstructure evolution of the lines. The measurement results showed that, when sintered at higher temperatures, the structure became denser with grain growth; however, significant central collapse of the lines and large interagglomerate pores increased electrical resistivity. [Copyright &y& Elsevier]

Ink-jet technology is a novel method for rapid deposition of accurately measured material with high precision. Consequently it has been used for applications such as, deposition of light emitting polymers and more recently for fabricating 3D objects and micro-mechanical structures. Ink-jet technology is also being applied to produce tactile maps for the visually impaired. The efficiency of the tactile maps, as outlined by psychophysical and cartographic studies of haptics, depends on its 3D features. To comprehend and control these features, detailed understanding of interaction amongst micro-drops, which are typically 50μm in diameter, is imperative. Multiphase interaction takes place between each liquid drop at impact with liquid or solid cured drops (deposited previously) and the solid substrate in an envelop of air. The behavior of micro-drops with regards to surface tension, drop coalescence among liquid and solid drops, drop impact kinetics, wettability, surface energy and drop spread has been analyzed using a computational model. [ABSTRACT FROM AUTHOR]

Abstract: Humidity-sensitive membranes made of ionene oligomer have been fabricated on the electrode substrate using a commercial drop-on-demand ink-jet printing system using a 15μm diameter nozzle driven by a piezoelectric device. After deposition and evaporation of the solvent, the humidity sensors have been cross-linked by heating. Their humidity-sensitive properties have been determined by using a thermostatic humidity chamber. Electrical measurements under various relative humidity were performed. The humidity-sensitive characteristics of sensors obtained by ink-jet printing technique were compared with that of dip-coating method. Humidity sensors showed a decrease in impedance as an increase of relative humidity and their impedance characteristics are in a close agreement. [Copyright &y& Elsevier]

Abstract: We developed a simultaneous UV embossing method to fabricate bank-shaped, two parallel layers with different surface properties in a one-step processing using the mold having loop-shaped protrusions. In conjunction with ink-jet technology, the molded pattern could be used as barrier ribs for particular flat panel displays. We choose the layer materials so that the bottom ink-philic one absorb jetted ink and the top ink-phobic one expel jetted ink. Therefore, the structure prevents ink from staining the barrier ribs’ surface and from mixing between adjacent pixels. The structure could be an effective barrier ribs for manufacturing of color filter of a liquid crystal display or light emitting layer of an electroluminescent display with high throughput. [Copyright &y& Elsevier]

Abstract: Microlens arrays and microoptical components in general are integral components in a wide range of high-tech products. The ability to fabricate such elements cheaply and with a high degree of accuracy is vital for the development of the next generation of optics-based technologies. There are currently a wide range of microoptical element fabrication technologies. These techniques all have advantages and disadvantages and no one technique is yet sufficient to meet all possible application criteria. One method that has been examined recently is the ink-jet deposition method. This method applies well-established ink-jet printer technology and is thus one possible candidate for large-scale fabrication of inexpensive components. The lenses fabricated using this method are normally found to have spherical profiles. In this paper, we examine the possibility of modifying the profile of these spherical lenses using an applied electric field (E-field). We note that the resulting aspheric lenses have a wide number of applications. These include beam shaping and power transfer applications including fiber coupling. In this paper we describe initial experiments involving single lenses. The single lenses produced using applied E-Fields differ significantly from lenses produced with no applied E-field. [Copyright &y& Elsevier]

Modified commercial ink-jet printers are simple and cost-effective tools for the fabrication of microarrays containing biological samples. In this paper, the two most common ink-dispensing technologies, thermal and piezoelectric, were investigated, tested, and compared in terms of their ease of use and spotting quality. Ink cartridges were used as sample reservoirs and refilled with small volumes (as low as 20 μL) of water-based sample solutions containing herring sperm DNA and fluorescent dyes. Different solution compositions were evaluated and compared. Microscopic spots (<200 μm) were printed on various membranes (cellulose, nylon, nitrocellulose, and Zeta-Probe) and glass microscope slides. This technique enabled rapid preparation of a large number of printed arrays of biological materials at extremely low cost. To further demonstrate the utility of the microarray platform, we performed an assay of Bacillus anthracis, detected through DNA hybridization using fluorescent probes complementary to the B. anthracis target printed on a membrane. A comparison of Zeta-Probe and nylon membranes yielded less non-specific binding when using the Zeta-Probe membrane. In addition, detection of 100 fmol of the target per printed spot was demonstrated. [Copyright &y& Elsevier]

The nonlinear dynamics of the impact and penetration of a liquid droplet in a radial capillary is studied numerically. The radial capillary is formed by two parallel plates at a distance of δg. The top plate has an orifice at its center. A droplet impacting on the orifice-plate partly spreads over the top plate, and the rest penetrates into the capillary gap between the two plates. The rate of spread of the fluid on the orifice plate, ξout, is governed by the contact angle, β, between the liquid and the orifice plate and the droplet initial momentum, whereas the rate of fluid spread inside the capillary gap, ξin, is decided by the contact angles with both plates and the plate gap, δg. [Copyright &y& Elsevier]

We report the catalytic synthesis of carbon nanotubes and two approaches to the catalyst patterning. Aligned multi-wall carbon nanotube (MWNT) arrays were synthesized in the presence of Co nanoparticles that were prepared by a reverse micelle method. By taking advantage of the fact that the Co nanoparticles are dispersible in organic solvent, an ink-jet technique has been applied to the Co nanoparticle dispersion for MWNT patterning. Single-wall carbon nanotubes (SWNTs) were synthesized by using Fe and Mo supported catalysts and the catalyst preparation process was combined with lithographic techniques, leading to formation of nanotubes bridging or crossing the catalyst patterns. These catalyst-patterning techniques, together with recent development of nanotube synthetic methods, may find applications in electronic and electrochemical applications, such as field-emission displays, nanodevices, and fuel cells. [Copyright &y& Elsevier]

Miniaturization and parallelization of fluorescence bioassays has gained ground in many fields of life sciences, pharmaceutical screening and chemical research and development. A heterogeneous fluorescence immunoassay for the detection of small analytes in nanoliter range using nanotiter plates (NTPs) is described. The phase-separation fluorescence immunoassay (PSFIA) is a competitive, heterogeneous immunoassay based on energy transfer to an immobilized acceptor dye at the surface of nanowells. [Copyright &y& Elsevier]

• Fabrication of arrayed microwells on PDMS substrates using ink-jet process was realized. • Microwells with wrinkle microstructures were fabricated by ink-jet and DLC deposition process. • The microwells showing the ability to form multicellular spheroids were obtained. • The fabrication process was expected to be used in PDMS-based microfluidic devices. Fabrication of microwells is an important technology to create and enhance the functions needed for the biological applications of microfluidic devices. In this paper, how to fabricate arrayed microwells on poly(dimethylsiloxane) (PDMS) substrates handily using an ink-jet processing was presented. More, the microwells having wrinkle microstructures with several μm size on the surfaces were fabricated by a combination procedure of the ink-jet and diamond-like carbon (DLC) thin film deposition. The shapes of the microwells were hexagon and circle, and the sizes were in the ranges of 100–170 μm in diagonal or diameter and 3–30 μm in depth. To investigate the effect of the microwells on cellular behaviors, mouse myoblast cells were cultured on the PDMS substrates. The results demonstrated that the microwells with wrinkle microstructures had the ability to form spherically shaped cell aggregates of around 100 μm size, which were considered to be multicellular spheroids. [ABSTRACT FROM AUTHOR]