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The rapid development of additive manufacturing, also known as three-dimensional (3D) printing, is driving innovations in both industry and academia. Direct ink writing (DIW), an extrusion-based 3D printing technology, can build 3D structures through the deposition of custom-made inks and produce devices with complex architectures, excellent mechanical properties, and enhanced functionalities. A paste-like ink is the key to successful printing. However, as new ink compositions have emerged, the rheological requirements of inks have not been well connected to printability, or the ability of a printed object to maintain its shape and support the weight of subsequent layers. In this review, we provide an overview of the rheological properties of successful DIW inks and propose a classification system based on ink composition. Factors influencing the rheology of different types of ink are discussed, and we propose a framework for describing ink printability using measures of rheology and print resolution. Furthermore, evolving techniques, including computational studies, high-throughput rheological measurements, machine learning, and materiomics, are discussed to illustrate the future directions of feedstock development for DIW. The goals of this review are to assess our current understanding of the relationship between rheological properties and printability, to point out specific challenges and opportunities for development, to provide guidelines to those interested in multi-material DIW, and to pave the way for more efficient, intelligent approaches for DIW ink development. [ABSTRACT FROM AUTHOR]

Inkjet-printed micro-patterns on hydrophobic surfaces have promising applications in the fabrication of microscale devices such as organic thin-film transistors. The low wettability of the surface prevents the inkjet-printed droplets from spreading, connecting to each other, and forming a pattern. Consequently, it is challenging to form micro-patterns on surfaces with low wettability. Here, we propose a sequential printing and drying method to form micro-patterns and control their shape. The first set of droplets is inkjet-printed at a certain spacing and dried. The second set of droplets is printed between these dry anchors on the surface with low wettability. As a result, a stable bridge on the surface with low wettability forms. This printing method is extended to more complicated shapes such as triangles. By implementing an energy minimization technique, a simple model was devised to predict the shape of the inkjet-printed micro-patterns while confirming that their equilibrium shape is mainly governed by surface tension forces. The gradient descent method was utilized with parametric boundaries to emulate droplet pinning and wettability of the anchors and to prevent convergence issues from occurring in the simulations. Finally, the energy minimization based simulations were used to predict the required ink to produce dry lines and triangles with smooth edges. [ABSTRACT FROM AUTHOR]

Calcium hexaaluminate (CaO·6Al 2 O 3 , CA 6) porous ceramics possess excellent properties, including low density and high surface area. However, their inherent brittleness presents challenges in traditional fabrication methods, especially in terms of on-demand molding of macroscopic geometries and modulation of pore structures at the micro and nano scales. In this study, a novel approach was developed for producing CA 6 porous ceramics by employing in-situ gelation-assisted direct ink writing with sodium alginate. This method allows for the precise molding of macroscopic geometries and incorporates reaction sintering to prepare hierarchical porous features with macroscopic and microscopic pores. During the slurry printing process, the sodium alginate present in the ceramic slurry undergoes gelation upon contact with the calcium chloride expelled from the atomizer, thus facilitating in-situ curing and shaping. The optimal formation temperature for CA 6 is 1550 °C, resulting in grains with a lamellar structure. The ceramics display predominant pore sizes of 346 nm, 5.59 μm, and 8.25 μm, with an apparent porosity of 70.72 %. This printing strategy employs a slurry that offers excellent compatibility and design flexibility, opening up possibilities for tailoring porous structures to precisely meet specific application requirements. [ABSTRACT FROM AUTHOR]

High-frequency transmission is limited to the skin depth in metals. Because poor conductivity cannot be compensated for by increasing the conductor thickness as with DC, optimal transport properties are prerequisites for radio frequency (RF) use. Structural and chemical analyses of transmission lines printed using a traditional ink consisting of Ag nanoflakes in a dispersing phase revealed that optimized thermal treatments yielded thorough burnout of the binder, significant grain growth, elimination of the pore volume, and electrical responses that were comparable to values obtained for thermally evaporated, fully dense Ag controls. Specifically, a low DC resistivity of 2.3 μΩ·cm (1.4× bulk Ag) and RF transmission coefficients of 0.87 and 0.75 at 5 GHz and 10 GHz, respectively, were measured in the nanoflake Ag prints. Conversely, in transmission lines printed from a metal-organic decomposition ink, residual chemical contamination impeded diffusion and densification, yielding greater porosity, small grains that are pinned, and a degraded RF response. Reasonably good porosity approximations were obtained from a model based on percolation theory. The results indicate that contaminants at interfaces and pore surfaces impede diffusion, pore elimination, and full densification, and further, alter carrier dynamics and degrade RF response. [ABSTRACT FROM AUTHOR]

Ultrahigh‐resolution X‐ray detection has always been a goal pursued in industrial inspection and medical diagnosis. However, the resolution of the corresponding image generally suffers from serious light scattering and crosstalk. Here, a low‐temperature thermoplastic scintillator ink of [Bmmim]2MnCl4 (Bmmim = 1‐butyl‐2,3‐dimethylimidazolium) is designed, achieving an astonishing spatial resolution of over 22 lp mm−1 (≥22.5 µm). A customized X‐ray imaging can be realized with the as‐explored [Bmmim]2MnCl4 scintillator to the targets through brushing feasibly exhibiting a high adhesion and processability thanks to the superior rheological properties. It is demonstrated that the coordination number determines the melting point of the corresponding scintillator, and an appropriate melting point (323 K) endows a superior viscosity of the sample as print ink. Accordingly, the as‐explored scintillator not only exhibits a high light output with 3.63 times of the commercial Bi4Ge3O12 (10 000 photons MeV−1) under steady‐state X‐ray illumination but also performs excellent recyclability even after 100 re‐uses. This work brings a new perspective for solving the problems of light scattering and light crosstalk for X‐ray imaging, as well as promoting the development of scintillator ink for recycling utilization. [ABSTRACT FROM AUTHOR]

The three-dimensional (3D) printing of biomaterials, cells, and bioactive components, including growth factors, has gained interest among researchers in the field of tissue engineering (TE) with the aim of developing many scaffolds to sustain size, shape fidelity, and structure and retain viable cells inside a network. The biocompatible hydrogel employed in 3D printing should be soft enough to accommodate cell survival. At the same time, the gel should be mechanically strong to avoid the leakage of cells into the surrounding medium. Considering these basic criteria, researchers have developed nanocomposite-based printable inks with suitable mechanical and electroconductive properties. These nanomaterials, including carbon family nanomaterials, transition metal dichalcogenides, and polymeric nanoparticles, act as nanofillers and dissipate stress across polymeric networks through their electroactive interactions. Nanofiber-reinforced printable ink is one kind of nanocomposite-based ink that comprises dispersed nanofiber components in a hydrogel matrix. In this current review, we compile various TE applications of nanofiber-reinforced printable ink and describe the 3D-printing parameters, classification, and impact of cross-linkage. Furthermore, we discuss the challenges and future perspectives in this field. [ABSTRACT FROM AUTHOR]

Keratoacanthoma (KA) is a common, low-grade, rapidly growing cutaneous squamous cell carcinoma that presents as an enlarging crateriform nodule, which may spontaneously involute but rarely metastasizes. Immunosuppression, ultraviolet light, viral infection, surgical procedures, and trauma are associated with their development. Overall, tattoo-induced squamous cell neoplasms are infrequently described in the literature. Carcinogenesis is hypothesized to result from trauma caused by the tattooing procedure or a foreign body reaction to the pigment. However, the pathogenesis has not been clearly deffned. While most commonly associated with red ink, to date, very few cases of KA forming within black, blue, or multicolored ink tattoos are reported. Herein, we describe a case of KA arising within areas of blue and black pigment in a decorative ink tattoo. [ABSTRACT FROM AUTHOR]

Summary The current state of data offers only insufficient possibilities for the risk assessment of tattoo inks. Furthermore, the long‐term exposure, the potential long‐term damage and the causes of many diseases associated with tattoos are not known (yet). Researchers from different countries are working on this question with the intention of understanding as much as possible about tattoos. This knowledge may then be applied to produce safer tattoo inks. [ABSTRACT FROM AUTHOR]

In this study, multi-level laminate-network boron nitride nanosheets (BNNSs)/TC4 composite with interlayer interlocking was fabricated using a facile direct ink writing (DIW) technique. In-situ 3D nano-configurations consisting of BNNSs and TiBx nanophases distributed around TC4 matrix particles formed the first-level network structure, while the above composite layers and TC4 layers with interlayer interlocking formed the second-level laminate structure. It exhibits a comparable high tensile strength of around 1203 MPa, compared to composites with a single-network structure, while demonstrating a 20% higher toughness of 55.8 MJ/m3. The interlayer interlocking microstructure interlayer could be responsible for the strength enhancement, which benefits the stress transfer between layers. The improved ductility could be attributed to the crack blocking adduced by the laminate structure and the 3D network in the composite layers. [ABSTRACT FROM AUTHOR]

3D-printed monolithic catalysts have attracted extensive attention in the petrochemical industry due to significant advantages of excellent circulation, mass and heat transfer efficiency and convenience. However, according to the characteristics of each chemical reaction, there are diversity and difficulty in the design of monolithic catalysts, especially the regulation of catalyst ink, the introduction of active centers and the construction of reaction pores. In this work, we report a preparation of ceramic-based catalysts with direct ink writing (DIW) 3D printing technology for ultra-deep oxidative desulfurization (ODS) of diesel. Through a series of rheological analyses of catalyst inks, the effects of ink composition and content on fluidity and viscoelasticity are explored for the forming mechanism of high-quality 3D printed inks. Besides, ionic liquids (ILs) [C 12 Vim] 3 PMo 12 O 40 and mordenite are cleverly introduced into the 3D printed ink for assisted construction of active center and reaction channel in functionalization of the ODS catalyst. The DBT removal of 3D-MoO 3 /BT-MOR can reach 100 % and this monolithic catalyst is easy to be separated from oil. This work is deeply focused on the preparation and molding of catalyst inks to achieve efficient monolithic catalysts that provide an excellent path for many industrial oxidation reactions. [ABSTRACT FROM AUTHOR]

Transfer of the designs to the surface of ceramic wall tiles is performed by ink-jet digital printing technology. CMYK ink colors are used in ink-jet printing technology. The similarities between hues for various color types make it difficult to come up with different designs. In this study, the development of a wall tile matte glaze recipe with high color activity, which can be worked with CMYK+Pink ink colors. Different recipes were developed by increasing the amount of calcite, dolomite, zinc oxide and magnesite ratios, respectively. Firstly, matt glaze recipes are prepared and employed on wall tile with engobe, followed by CMYK+Pink ink digital decor application. Succeeding the sintering of tiles, L,a,b color measurements of ink decorated glaze recipes were made, and it was determined that the value of 'a' increased from 15.35 to 22.18. The hue angle and chroma values of the recipies were calculated. No significant differences were observed in the color activities of the colors other than pink, and the desired pink color intensity was achieved with one of the new wall tile matte glaze recipes. It was observed that the pink color intensity increased with the increase in the amount of CaO in the content of the matte glaze recipe. The color activity of the pink color could is not obtained in the glaze recipe where the amount of ZnO increased. [ABSTRACT FROM AUTHOR]

[Display omitted] Thin-film sensors are essential for real-time monitoring of components in high-temperature environments. Traditional fabrication methods often involve complicated fabrication steps or require prolonged high-temperature annealing, limiting their practical applicability. Here, we present an approach using direct ink writing and laser scanning (DIW-LS) to fabricate high-temperature functional thin films. An indium tin oxide (ITO)/preceramic polymer (PP) ink suitable for DIW was developed. Under LS, the ITO/PP thin film shrank in volume. Meanwhile, the rapid pyrolysis of PP into amorphous precursor-derived ceramic (PDC) facilitated the faster sintering of ITO nanoparticles and improved the densification of the thin film. This process realized the formation of a conductive network of interconnected ITO nanoparticles. The results show that the ITO/PDC thin film exhibits excellent stability, with a drift rate of 4.7 % at 1000 °C for 25 h, and withstands temperatures up to 1250 °C in the ambient atmosphere. It is also sensitive to strain, with a maximum gauge factor of −6.0. As a proof of concept, we have used DIW-LS technology to fabricate a thin-film heat flux sensor on the surface of the turbine blade, capable of measuring heat flux densities over 1 MW/m2. This DIW-LS process provides a viable approach for the integrated, rapid, and flexible fabrication of thin film sensors for harsh environments. [ABSTRACT FROM AUTHOR]

Decellularized extracellular matrix (dECM) retains the bioactive components to mimic tissue‐specific microenvironment. Designing dECM‐based inks for 3D printing to prepare scaffolds can enhance the regeneration of corresponding tissues. However, due to the strict requirements for inks, how to efficiently prepare dECM‐based inks is a challenge. Inspired by granular lubrication, the present study proposes an effective and general method for preparing granular ink from dECM microparticles (MP) with high content. Through dopamine polymerization, dECM‐MPs are coated with polydopamine (PDA). Meanwhile, gelatin methacryloyl (GelMA)‐based microspheres (GelMA‐MSs) are prepared with available double bonds. dECM‐MPs (30–40 wt%) and GelMA‐MSs assemble to form a granular ink, exhibiting well‐performed extrudability, plasticity, and fidelity. Further inspired by joint lubrication, hyaluronic acid (HA) is introduced into PDA coating and GelMA‐MSs to reduce the micro‐interface friction, further promoting the printability and broadening the printable window of dECM‐MPs content to 30–60 wt%. Osteochondral scaffold and skin wound dressing are fabricated through 3D printing from the corresponding dECM‐MPs, enhancing the regeneration of the corresponding tissues in vivo. Especially, the realization of printability of highly rigid dECM‐MPs confirms the universality, reliability and efficiency of the present strategy. [ABSTRACT FROM AUTHOR]

Surface interactions of the materials during and after the printing process are extremely important for understanding and optimizing the process of graphic reproduction. In screen printing on porous and absorbent substrates, mesh type and ink composition significantly influence the properties of the printed product. To protect the absorbent printing substrates such as board from moisture penetration and to ensure the optimal interaction of the printed ink layer and the substrate, board substrates can be coated with protective primers before printing. In this research, biodegradable primers made of poly(ɛ-caprolactone) and poly(lactic acid) were applied on the board substrate which was then screen-printed using two screen rulings of the mesh and two different types of water-based printing inks on unprimed and primed board substrates. Printed ink layer thickness, surface roughness, water vapor transmission rate, surface free energy and adhesion parameters were measured/calculated on all produced samples. Microscopy of the printed elements was performed to visualize the influence of the primers on the printed line edge. Results of the research have shown that the primers influence the roughness reduction of the printed ink layer. Furthermore, thickness of the printed ink layers increased when the primers were applied on the substrate, pointing to the decreased permeability of the board, which was confirmed by the reduced water vapor transmission rate of the primed and printed substrates. The surface free energies of the tested surfaces and the adhesion parameters between biodegradable primers and prepared printing inks differed depending on the type of the ink and primer, pointing to the optimal combination of the primer and ink for the favorable acceptance of printing ink on the substrate. Results of this research have enabled the optimization of the quality of screen-printed board product. [ABSTRACT FROM AUTHOR]

• First, reproduction of byzantine iron gall ink recipes with natural raw ingredients on hemp handmade paper and goatskin parchment. • Iron-Gall mock-ups were examined by elemental and molecular spectroscopic techniques before and after thermal accelerating ageing. • µ-Raman spectroscopy revealed modification of main bands and increase fluorescence after thermal accelerating ageing. • SEM-EDS documented the different formation of crystal aggregates in the cellulosic fibers compared to those in the parchment and increased sulfur content. • The spectroscopic data elucidate degradation pathways and the possible effect of raw ingredients. Understanding the mechanism of iron gall ink corrosion and degradation is essential for the selection and implementation of a successful conservation treatment to ensure their preservation. Recipe reproduction and diagnostic analysis of corrosion products may assist to understand this mechanism. This study aims to reconstruct iron gall inks using the instruction mentioned in Byzantine and Post-Byzantine recipes, with natural ingredients comparable to pure compounds. The inks were applied on different substrates (paper, parchment) and submitted to thermal accelerated ageing. Artificially aged inks were examined with SEM-EDS that revealed the different formation of crystal deposits in paper and parchment, whereas suggested an increasing percentage of sulphur, corresponding to sulfate ions that accelerated catalytic acid hydrolysis. Furthermore, µ-Raman spectra indicate the possibility of the bond weakening between the ink molecules and elucidates the mechanism of iron gall inks degradation. An increase of fluorescence was also observed to ink degradation and excess amount of added organic compounds. [ABSTRACT FROM AUTHOR]

In Chinese paintings, the marriage of rice paper and ink is the soul of this art. Ink possesses a highly distinctive "color" expressiveness. By employing ink, various shades of black and diverse color effects can be portrayed, making the image more rich, vibrant, and three-dimensional on a rice paper. However, when used in traditional ink wash painting, the flow and penetration of conventional ink is difficult to control, and its carbon black particles make it a challenge to achieve multiple transparent gradients. Considering the water solubility and two-dimensional nanostructure of graphene oxide (GO), the authors of this paper has developed and proposed the use of water-based GO ink for Chinese ink wash painting, aiming to endow it with new aesthetic forms and unique expressive potentials. [ABSTRACT FROM AUTHOR]

Accurately assessing the color quality of printed products becomes intricate when optical brightening agents (OBAs) are introduced in papers, as diverse interactions occur among different ink pigments and papers containing OBAs due to variations in ink formulation chemistries. Specifically, alkali‐based pigments, commonly used as spot colors, are carefully formulated to ensure consistency across production batches. The presence of OBAs, which absorb ultraviolet light and emit it in the visible spectrum, significantly affects color perception and accuracy on paper when interacting with these inks. This research marks an initial investigation into how OBAs in paper influence the color accuracy of five distinct alkali‐based spot color paste inks using a Little Joe ink proofer. The research examines the physical, optical, and colorimetric characteristics of two paper samples‐one with OBA and one without‐ and analyzes the colorimetric changes occurring during the ink drying process. The results indicate that reflex blue, purple, and violet spot colors achieved acceptable delta E (ΔE00) value of below 3 on non‐OBA paper, with rubine red being on the borderline at 3.1 after 48 h. In contrast, purple, rhodamine red and violet achieved acceptable ΔE00 below 3 on high OBA paper. The distinct behavior exhibited by certain inks led to the conclusion that achieving a consistent proofing procedure across diverse alkali‐based ink formulations is impractical. [ABSTRACT FROM AUTHOR]

Macrophages play a critical role for the persistence of tattoo ink in human skin. However, a comparison to other skin‐resident and blood circulating immune cells and a profound analysis of REACH‐compliant tattoo ink are unmet medical needs. We hence characterized the size distribution of ink particles using physicochemical methods. We studied the uptake of tattoo ink by key human skin cells and blood‐derived immune cells using optical and electron microscopy as well as flow cytometry. Scanning electron microscopy of ink revealed its crystalline structure, and a tendency towards aggregations was indicated by size changes upon diluting it. Flow cytometric analyses of skin and immune cells after incubation with tattoo ink demonstrated an increase in cellular granularity upon uptake and red ink additionally evoked fluorescent signals. Human macrophages were most potent in internalizing ink in full thickness 3D skin models. Macrophage cultures demonstrated that the ink did not lead to elevated inflammatory mediators, and showed no indications for toxicity, even after nice days. Strikingly, monocytes were most efficient in ink uptake, but displayed reduced viability, whereas granulocytes and lymphocytes showed only temporary ink uptake with flow cytometric signals declining after 1 day. Mechanistic studies on ink retention by corticosteroids or dexpanthenol in macrophage cultures demonstrated that these compounds do not lead to ink excretion, but even slightly increase the ink load in macrophages. The highly motile monocytes, precursors of macrophages, may play an underrated role for tattoo ink translocation from dermal blood vessels into internal organs. [ABSTRACT FROM AUTHOR]

Though books are often considered “old media” in the digital age, their production in this period in fact has been continually reimagined and redefined through new technologies of printing, especially paper and ink manufacturing. This paper explores how three specific recent printed books demonstrate this point in both form and content: David Brower’s Let the Mountains Talk, Let the Rivers Run (1995), William McDonough and Michael Braungart’s Cradle to Cradle (2002), and the 2008 Harper-Collins Green Bible. Brower’s book was printed on paper made from kenaf, a sustainable alternative to wood-based paper. Cradle to Cradle was printed on a synthetic polymer that could be endlessly remade into other products. The Green Bible was printed on recycled paper and used soy-based ink, and all verses with environmental content were printed in green. In each case, in form these printed books were meant to model innovative industrial information production while also through their content to motivate enhanced environmental consciousness.

This study reports the use of tin oxide (SnO 2) octahedral nanoparticles with exposed high-energy facets as sensing material in inkjet-printed carbon monoxide (CO) gas sensors. The nanoparticles were synthesized via a hydrothermal method aimed at encouraging high-indexed (221) crystal planes to be exposed as facets, since their high surface energy may encourage interactions with gases. Studies by X-ray diffraction (XRD) confirmed the identity of the SnO 2 , while transmission electron microscopy (TEM) revealed formations of octahedral-shaped SnO 2 nanoparticles, with features confirming the exposure of high-energy (221) crystal facets. The nanoparticles' reductive behavior in a CO environment was studied using temperature-programmed reduction (TPR). A stable ink based on the SnO 2 nanoparticles was successfully prepared and utilized to fabricate, via inkjet printing, homogenous films onto electrically conductive graphene-based interdigitated electrodes. Optimizing the inkjet printing parameters enhanced the CO gas sensing performance of the fabricated sensors. For example, at 200 ppm, the sensor with 10 printed layers recorded a sensitivity of about 20%, as compared to a sensitivity of not more than 14% recorded in each of the sensors with 5, 15, and 20 printed layers. As a result of having homogenous films, the inkjet-printed sensors also exhibited almost double the sensitivity of similar sensors prepared by drop-casting method. [Display omitted] [ABSTRACT FROM AUTHOR]

The increasing adoption of additive manufacturing (AM), also known as 3D printing, is revolutionizing the production of wearable electronics and energy storage devices (ESD) such as batteries, supercapacitors, and fuel cells. This surge can be attributed to its outstanding process versatility, precise control over geometrical aspects, and potential to reduce costs and material waste. In this comprehensive review, major AM processes like inkjet printing, direct ink writing, fused deposition modeling, and selective laser sintering/melting along with possible configurations and architectures, are elaborately discussed for each bespoke ESD. The application of 3D‐printed energy storage devices in wearable electronics, Internet of Things (IoT)‐based devices, and electric vehicles are also mentioned in the review. The role of AM in facilitating the production of solid‐state batteries has also revolutionized the electric vehicle (EV) industry. Recent progress in the field of AM of energy systems with solid electrolytes and potential future directions such as 4D printing to incorporate stimuli‐responsive behavior in 3D‐printed materials, biomimetic design optimization, and additive manufacturing of ESD in a micro‐gravity environment have also been highlighted. Extensive research and continuous progress in this field are expected to enhance the longetivity, industrial scalability, and electrochemical performance of 3D‐printed energy storage devices in future. [ABSTRACT FROM AUTHOR]

In this study, pink colour development was investigated by changing systemically alkaline and alkaline earth ratios of the developed glaze. Group-1 (Na 2 O/CaO, Na 2 O/MgO, Na 2 O/BaO) and Group-2 (CaO/MgO, CaO/BaO) represent compositional variations. Group-1 has alkaline oxides with changing ratios of 0.2 mol Na 2 O and 0.6 mol CaO and 0.2 mol Na 2 O and 0.2 mol BaO, respectively. These ratios vary as 0.2 mol CaO and 0.1 mol BaO in Group-2. According to the results, the pink colour intensity was improved in the compositions with cassiterite (SnO 2) and malayaite CaSn(SiO 5) phases. In addition, bar-shaped BaO–CaO–Al 2 O 3 –SiO 2 crystals were observed in structures with high barium oxide content. It could be concluded that the pink colour development regarding the a* (redness) value may also be related to the presence of BaO–CaO–Al 2 O 3 –SiO 2 [ABSTRACT FROM AUTHOR]

Electrowetting with a dielectric layer is commonly preferred in practical applications. However, its potential is often limited by factors like the properties of the dielectric layer and its breakdown, along with the complexity of the deposition method. Fortunately, advancements in 3D inkjet printing offer a more adaptable solution for making patterned functional layers. In this study, we used a negative photoresist (HN-1901) to create a new dielectric layer for an electrowetting display on a 3-inch ITO glass using a Dimatix DMP-2580 inkjet printer. The resulting devices performed better due to their enhanced resistance to dielectric breakdown. We meticulously investigated the physical properties of the photoresist material and printer settings to achieve optimal printing. We also controlled the uniformity of the dielectric layer by adjusting ink drop spacing. Compared to traditional electrowetting display devices, those with inkjet-printed dielectric layers showed significantly fewer defects like bubbles and electrode corrosion. They maintained an outstanding response time and breakdown resistance, operating at an open voltage of 20 V. Remarkably, these devices achieved faster response times of ton 22.3 ms and toff 14.2 ms, surpassing the performance of the standard device. [ABSTRACT FROM AUTHOR]

All inkjet‐printed thermal sensors are manufactured based on a metal–insulator–metal (MIM) interface or capacitor architecture, for the adapted device size ranging from 16 to 36 mm2 active area. Two different material inks, namely a nanoparticle conductive silver ink and an inorganic‐polymer‐based hybrid insulator ink, are applied layer by layer on a thin flexible polyimide substrate, for developing the printed MIM devices. To ensure the desired electronic conductivity and insulation from the layers, the manufacturing process steps and parameters are tuned, accordingly. The results show that the inkjet‐printed MIM devices could constitute up to 15 μm thickness and demonstrate average detection of a change in electrical capacitance ranging from 20 to 100 pF, when the temperature is varied between 100 and 300 °C. The investigations also summarize that the change in the electrical response is enough to detect an increment of 50 °C. The printed sensors also display high operational stability and repeatability, when subjected to thermal cycling. [ABSTRACT FROM AUTHOR]

Despite the great success of perovskite photovoltaics in terms of device efficiency and stability using laboratory‐scale spin‐coating methods, the demand for high‐throughput and cost‐effective solutions remains unresolved and rarely reported because of the complicated nature of perovskite crystallization. In this work, we propose a stable precursor ink design strategy to control the solvent volatilization and perovskite crystallization to enable the wide speed window printing (0.3 to 18.0 m/min) of phase‐pure FAPbI3 perovskite solar cells (pero‐SCs) in ambient atmosphere. The FAPbI3 perovskite precursor ink uses volatile acetonitrile (ACN) as the main solvent with DMF and DMSO as coordination additives is beneficial to improve the ink stability, inhibit the coffee rings, and the complicated intermediate FAPbI3 phases, delivering high‐quality pin‐hole free and phase‐pure FAPbI3 perovskite films with large‐scale uniformity. Ultimately, small‐area FAPbI3 pero‐SCs (0.062 cm2) and large‐area modules (15.64 cm2) achieved remarkable efficiencies of 24.32 % and 21.90 %, respectively, whereas the PCE of the devices can be maintained at 23.76 % when the printing speed increases to 18.0 m/min. Specifically, the unencapsulated device exhibits superior operational stability with T90>1350 h. This work represents a step towards the scalable, cost‐effective manufacturing of perovskite photovoltaics with both high performance and high throughput. [ABSTRACT FROM AUTHOR]

Online pharmacies and social media platforms are responsible for the growing presence of counterfeit medicines, and the verification and authentication of dosage levels are imperative for protecting individual medicines. However, the existing anticounterfeit methods for medicines and exterior box‐level protection are often limited, and they focus on pharmaceutical supply chains instead of empowering patients. Here, bioprinting and taggant construction of camouflaged biosafe quick response (QR) codes are introduced for on‐dose (or in‐dose) medicine security, integrated with the dosage form. Machine‐readable color QR codes contain concealed invisible patterns with biologically safe near‐infrared absorption properties, which help enhance the security of conventional QR codes. The reported bioinkjet printing and protein taggant construction guarantee printability, imperceptibility, stability, biocompatibility, digestibility, and tamper resistance to be an inherent part of each unit of medicine in solid dosage formats. Camouflaged biosafe QR code taggants can offer various medicine security applications including anticounterfeit measures, authentication features, track‐and‐trace, and serialization at the dosage level. This approach is expected to empower patients to play an active role in fighting illicit medicines and pharmaceutical products. [ABSTRACT FROM AUTHOR]

This study presents a strategy of design and development of inkjet‐printable and UV‐curable quantum dot (QD) polymer‐based inks and color conversion (CC) film for use in optoelectronic devices. At first, the preparation of a QD ink is focused on two key aspects, that are QD chemical compatibility and ink printability. In the hybrid organic–inorganic polymer/QDs system, it must be formulated to a well‐dispersed ink, in which a dispersant additive without negative effect on QDs is introduced to enhance the QD suspension. As the optical density of final dried QD film is one of the most critical concerns in color conversion, QD concentration should be as high as possible in the ink, which increases the ink viscosity. Consequently, a trade‐off between QD concentration and the ink viscosity associated with the ink‐jetting temperature is considered to ensure the ink printability. Finally, the designed QD ink is printed as color conversion film on a mini‐LED panel composed of two violet mini‐chips to produce red and green emissions, while blue emission directly comes from a blue mini‐chip. The final conversion efficiency of QDCC on mini‐LED panel are between 35% and 45%, showing the promising applications in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Visual display is a crucial aspect of courtship, and their success relies on both display quality and the surrounding environment, such as the visual background. Cephalopods may release ink when attacked by predators or during aggressive interactions with conspecifics. Here, we report that ink is used as a part of the courtship display by males of the cuttlefish species Sepia andreana. Males of this species engage in a highly ritualized multimodal courtship using a pair of markedly long sexually dimorphic arms. At the climax of the courtship, the male releases a diffuse backdrop of ink near himself and then performs the specific courtship display by extending his sexually dimorphic arms and altering his body pattern to pale in front of this ink backdrop, and then proceeds to mate. This novel use of cephalopod ink could make the surroundings darker and more homogeneous, potentially serving as a temporary modification of the visual environment for courtship display. [ABSTRACT FROM AUTHOR]

An investigation of a single‐layer band‐stop frequency selective surface (FSS) is designed and analyzed for X‐band application. The proposed FSS design primarily involves a cross‐shaped conductive patch with four square slots on each corner, and it is fabricated on the 3D‐printed polylactic acid (PLA) substrate. The design is resonating at 12 GHz with an insertion loss greater than 60 dB. The 10 dB bandwidth of the designed structure is 8.3% with respect to the resonant frequency. The results show that the design has polarization‐independent and angle‐insensitive transmission characteristics for incidence angles up to 60°. The simulation is carried out using CST Microwave Studio Suite, and the results are obtained. The physical mechanism of the designed structure is evaluated using the surface current distribution. The designed FSS is fabricated using two techniques, namely inkjet printing and conventional etching. Finally, the measurements of the fabricated structure are done using a vector network analyzer setup. [ABSTRACT FROM AUTHOR]

Viscoelastic properties of 3D printable peanut‐based food ink were investigated using frequency sweep and relaxation test. The incorporation of xanthan gum (XG) improved the shear thinning behavior (n value ranging from 0.139 to 0.261) and lowered the η*, G′, and G′′ values, thus making food ink 3D printable. The addition of XG also caused a downward shift in the relaxation curve. This study evaluates the possibility of an artificial neural network (ANN) approach as a substitute for the Maxwell three‐element and Peleg model for predicting the viscoelastic behavior of food ink. The results revealed that all three models accurately predicted the decay forces. The inclusion of XG decreased the hardness and enhanced the cohesiveness, so enabling the 3D printing of food ink. The hardness was highly positively correlated with Maxwell model parameters Fe, F1, F2, F3, and Peleg constant k2 (0.57) and negatively correlated with k1 (−0.76). [ABSTRACT FROM AUTHOR]

Three-dimensional printed electrodes seem to overcome many structural and operational limitations compared to ones fabricated with conventional methods. Compared to other 3D printing techniques, direct ink writing (DIW), as a sub-category of extrusion-based 3D printing techniques, allows for easier fabrication, the utilization of various materials, and high flexibility in electrode architectures with low costs. Despite the conveniences in fabrication procedures that are facilitated by DIW, what qualifies an ink as 3D printable has become challenging to discern. Probing rheological ink properties such as viscoelastic moduli and yield stress appears to be a promising approach to determine 3D printability. Yet, issues arise regarding standardization protocols. It is essential for the ink filament to be extruded easily and continuously to maintain dimensional accuracy, even after post-processing methods related to electrode fabrication. Additives frequently present in the inks need to be removed, and this procedure affects the electrical and electrochemical properties of the 3D-printed electrodes. In this context, the aim of the current review was to analyze various energy devices, highlighting the type of inks synthesized and their measured rheological properties. This review fills a gap in the existing literature. Thus, according to the inks that have been formulated, we identified two categories of DIW electrode architectures that have been manufactured: supported and free-standing architectures. [ABSTRACT FROM AUTHOR]

Transition metal dichalcogenides (TMDs) are promising 2D materials which are attracting significant interest because of their distinctive physicochemical properties. The possibility of being exfoliated and dispersed in liquid solutions offers a viable pathway to scalable production. This personal account focuses on recent advancements in 2D TMD inks produced by liquid‐phase exfoliation (LPE) methods and intercalation‐based electrochemical exfoliation. In particular, different LPE production strategies, like ultrasonication LPE, high‐shear mixing exfoliation, and microfluidization, are introduced alongside a broad range of liquid media employed to provide functionalized TMD inks. The main advantage of TMD inks is its scalability, for practical applications in printed optoelectronics, energy storage, and conversion. Furthermore, the chemical functionalization of TMD inks can solve the poor electrical conductivity attributed to edge defects inherent in TMD inks. Finally, the ultimate orientations for future applications of chemically functionalized TMD devices are forecasted, with a specific focus on wearable and flexible printed electronics. [ABSTRACT FROM AUTHOR]

Multi-channel and multi-parameter near-infrared spectroscopy (NIRS) has gradually become a new research direction and hot spot due to its ability to provide real-time, continuous, comprehensive indicators of multiple parameters. However, multi-channel and multi-parameter detection may lead to crosstalk between signals. There is still a lack of benchmarks for the evaluation of the reliability, sensitivity, stability and response consistency of the NIRS instruments. In this study, a set of test methods (a human blood model test, ink drop test, multi-channel crosstalk test and multi-parameter crosstalk test) for analyzing crosstalk and verifying the reliability of NIRS was conducted to test experimental verification on a multi-channel (8-channel), multi-parameter (4-parameter) NIRS instrument independently developed by our team. Results show that these tests can be used to analyze the signal crosstalk and verify the reliability, sensitivity, stability and response consistency of the NIRS instrument. This study contributes to the establishment of benchmarks for the NIRS instrument crosstalk and reliability testing. These novel tests have the potential to become the benchmark for NIRS instrument reliability testing. [ABSTRACT FROM AUTHOR]

In the psychology of aesthetics, compared with appreciation, there are fewer studies on art creation. This study aims to examine the influence of art creation on appreciation using haiku poetry with reference to the Mirror Model—a process model combining creation and appreciation. Although the model has been primarily used to examine visual arts, we examine its applicability to linguistic arts. In addition, we use ink painting to examine whether a generalisation across artistic genres can occur. The 115 participants were divided into two conditions—creation and control. The former created haiku before and after appreciation, while the latter did not create any haiku. The results showed no improvement in evaluation through creation. Additionally, recognising the difficulty related to creation leads to aesthetic evaluation, and this relationship is mediated by awe. These results expand the existing information regarding the Mirror Model in terms of the different art genres. [ABSTRACT FROM AUTHOR]

This paper presents a versatile nanotransfer printing method for achieving large-area sub-micron patterns of functional materials. Organosilicate ink formulations combined with effective release layers have been shown to facilitate patterning of materials through the commonly used patterning approaches—lift off, physical etching and chemical etching. In this paper, we demonstrate that organosilicate ink formulations function as an effective resist owing to its superior physico-chemical stability whereas the release layers ensure clean removal of the resist post patterning. We successfully demonstrate patterning of sub-micron structures (800 nm feature sizes) of chromium metal through the lift off approach, silicon through reactive ion etching technique and silicon dioxide through wet chemical etching technique illustrating the versatility of the reported method. This patterning methodology represents a significant advancement in enabling nanostructure fabrication within resource-constrained laboratories. The approach requires nothing more than a master mold containing the desired structures, a spin coater, a low-temperature hotplate, and a desktop reactive ion etch tool. [ABSTRACT FROM AUTHOR]

Inkjet-printable ink formulated with graphene oxide (GO) offers several advantages, including aqueous dispersion, low cost, and environmentally friendly production. However, water-based GO ink encounters challenges such as high surface tension, low wetting properties, and reduced ink stability over prolonged storage time. Alkali lignin, a natural surfactant, is promising in improving GO ink's stability, wettability, and printing characteristics. The concentration of surfactant additives is a key factor in fine-tuning GO ink's stability and printing properties. The current study aims to explore the detailed effects of alkali lignin concentration and optimize the overall properties of graphene oxide (GO) ink for drop-on-demand thermal inkjet printing. A meander-shaped temperature sensor electrode was printed using the optimized GO ink to demonstrate its practical applicability for commercial purposes. The sensing properties are evaluated using a simple experimental setup across a range of temperatures. The findings demonstrate a significant increase in zeta potential by 25% and maximum absorption by 84.3%, indicating enhanced stability during prolonged storage with an optimized alkali lignin concentration compared to the pure GO dispersions. The temperature sensor exhibits a remarkable thermal coefficient of resistance of 1.21 within the temperature range of 25 °C–52 °C, indicative of excellent sensitivity, response, and recovery time. These results highlight the potential of alkali lignin as a natural surfactant for improving the performance and applicability of inkjet-printable GO inks in various technological applications. [ABSTRACT FROM AUTHOR]

Among the various anti‐counterfeiting solutions, fluorescent compounds gained attention as challenging to copy solutions because of astute technological improvements. However, fluorescent compound usage in counterfeit detection is limited due to high price of rare earth metals, the low photostability of pigments or organic dyes, and the long‐term toxicity of conventional semiconductor quantum dots. Herein lies the value of carbon dot, a very stable, reasonably priced, and environmentally friendly material with intriguing features. In this work the development of blue fluorescent, N‐doped carbon dots (NCD) from waste bamboo stem cuttings via hydrothermal route is presented as an environmentally friendly approach to reduce the risk of toxic gas evolution from burning of bamboo waste. The carbon dot's practical application in anti‐counterfeit printing was ascertained by comprehending it's superior properties, such as high water solubility, eco‐friendliness, dazzling fluorescence, and surface functionalization through various characterization techniques. Inkjet printing of the designs on paper substrate using the aqueous NCD ink displayed reversible encryption‐decryption ability through variation of pH. The development paves the way for value‐added utilization of waste bamboo cuttings in fluorescent ink production. [ABSTRACT FROM AUTHOR]

Amphiphilic block copolymers-based aqueous color inks show great potential in the field of visual communication design. However, the conventional step-by-step chemistry employed to synthesize the amphiphilic block copolymers is intricate, with low yield and high economic and environmental costs. In this work, we present a novel method for preparing an amphiphilic AB di-block copolymer of PCL-b-PAA by employing a combined polymerization strategy that involves both cationic ring-opening polymerization (ROP) of the ε-caprolactone monomer and the reversible addition–fragmentation chain-transfer (RAFT) polymerization on the acrylic acid monomer simultaneously. The corresponding polycaprolactone (PCL) and polyacrylic acid (PAA) serve as the hydrophobic and hydrophilic units, respectively. The effectiveness of the amphiphilic AB di-block copolymer as the polymeric pigment dispersant for water-based color inks is evaluated. The amphiphilic AB di-block copolymer of PCL-b-PAA exhibits a molecular weight of 1400 g mol−1, which is consistent with the theoretical value and suitable for polymeric dispersant application. The high surface excess (Γmax) of the PCL-b-PAA in water indicates a densely packed molecular morphology at the water/air interface. Additionally, micelles can be stably formed in the aqueous PCL-b-PAA solution at very low concentrations by demonstrating a low CMC value of 10−4 wt% and a micelle dimension of approximately 30 nm. The model ink dispersion is prepared using organic dyes (Disperse Yellow 232) and the amphiphilic block copolymer of PCL-b-PAA. The dispersion demonstrates near-Newtonian behavior, which is highly favorable for the application as inkjet ink. Furthermore, the ink dispersion displays a low viscosity, making it particularly suitable for visual communication design and printing purposes. Moreover, the ink dispersion demonstrates an unimodal distribution of the particle size, with an average diameter of approximately 500 nm. It retains exceptional stability of dispersion and even conducts a thermal aging treatment at 60 °C for 5 days. This work presents a facile and efficient synthetic strategy and molecular design of AB di-block copolymer-based dispersants for dye dispersions. [ABSTRACT FROM AUTHOR]

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 77.6 m Ω □−1 sheet resistance in <20 ms, the quickest annealing procedure, without damaging flexible substrates. Flexible organic light‐emitting diodes (OLEDs) are created with a large active area (500 mm2) to demonstrate the efficacy of the flexible hybrid electrodes and the excellent bending stability (4 mm bending radius) of OLEDs. Maximum current efficiency of 19.58 cd A−1 and a maximum luminescence of 8708 cd m−2 at a low turn‐on voltage of 3.1 V for the small‐area (16 mm2) 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. [ABSTRACT FROM AUTHOR]

A novel determination method for protein biomarkers based on on-chip flow rate measurement was developed using a microchip with organic photodiodes (OPDs). This quantitative method is based on the flow rate measurement of an ink solution pushed out by oxygen gas generated through catalase reaction. The amount of oxygen gas generated in the sample reservoir is dependent on the concentration of the analyte; therefore, the flow rate of the ink solution is also dependent on the concentration of the analyte. The concentration of the analyte can thus be estimated by measurement of the ink solution flow rate. The ink solution flow rate was estimated by measuring the migration time of the ink solution between two points using two OPDs placed below the microchannel. The principle of this method was demonstrated by the measurement of catalase using the microchip. In addition, the developed method was applied to the determination of C-reactive protein (CRP), a biomarker of inflammation, based on a catalase-linked immunosorbent assay (C-LISA). The limit of detection for CRP was 0.20 µg/mL. The method was also applied to the determination of CRP in human serum, and the quantitative values obtained by this method were in excellent agreement with those obtained by the conventional enzyme-linked immunosorbent assay (ELISA) method. The developed method does not require a photodetector with high sensitivity and is thus capable of downsizing; therefore, this will be useful for on-site analyses such as point-of-care testing and field measurements. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to optimize the key parameters (mesh count, paper type and ink type) in screen printing, which are affecting the printed ink volume. The objective of the optimization was to maximize the color reliability by decreasing the color difference (ΔE value) of the prints while minimizing the ink consumption. Screen printing is still dominating the printing industry to make cost-effective production when high volumes are needed. Design/methodology/approach: The experiment was designed using the Taguchi method, and the samples were prepared with screen-printing by using the standard squeegee angle and pressure. The effect of mesh count, ink type and paper type on ink consumption was evaluated with using analysis of variances and main effects plots of S/N ratio and standard deviation. Findings: The factors ink type, paper type and mesh count were found significant for ink consumption due to their Probability (P) values which were lower than 0.05. It was determined that the mesh count was the most critical variable with the analysis of variance. The analysis showed that the selection of an optimum mesh count was the key to controlling the amount of the deposited ink. Although mesh counts were inversely proportional with the ink consumptions, they did not affect the color differences as expected. Originality/value: The optimization of process parameters, that are most effective on the print quality, is necessary to minimize the ink usage and lower the costs and environmental impact without exceeding the desired ΔE value limits. [ABSTRACT FROM AUTHOR]

Current methods lack one-step actuation programming for weave structures that can achieve multimodal motions in fiber and fabric actuators. Fiber and fabric actuators with dual-response to magnetic fields and near-infrared (NIR) light were fabricated via direct ink writing (DIW) in this work, and have 105.3 J kg−1 energy density, enabling multimodal motions including rolling, grasping, and transportation. [ABSTRACT FROM AUTHOR]

In the current study, the squid, Sepioteuthis lessoniana ink was used as a raw material. It summarizes physicochemical, elemental, and spectral properties (UV/Visible spectroscopy and FT-IR) of crude ink, whereas the biochemical analysis was performed with crude ink (CI) as well as melanin-free ink (MFI). The percentage yield was analyzed using various solvent extracts of CI and MFI. GC–MS was performed for the chemical constituents of the methanolic extract of ink. Furthermore, the methanolic extract was subjected to various biological applications. The physicochemical analysis defines the presence of moisture, ash, extractive value, solubility, and thermal stability of CI. The biochemical analysis reveals protein, lipid, and carbohydrate of 2.5, 2.2, and 2.37 mg/ml for CI and 2.8, 3.7, and 4.51 mg/ml for MFI respectively. The extract showed the highest zone of inhibition at 100 μg/ml. The antioxidant activity reveals the highest percentage of radical-scavenging activity in nitric oxide (NO) (89%), and total antioxidant capacity (TAC) assay showed the highest inhibition activity of 0.41 nm at 100 µg/ml. The cytotoxic ability of methanolic extract against MDA-MB-231 breast cancer cell line revealed an IC50 value of 10.13 μg/ml. Toxicity assay showed increased mortality of Artemia nauplii at higher concentrations (1000 ppm/40%) of extract. These findings indicate that S. lessoniana ink is a novel prospective product that needs to be characterized in order to increase its pharmacological activity. [ABSTRACT FROM AUTHOR]

Chrome plating will be banned in all new cars starting in 2024 due to health-related issues, including the risk of lung cancer. The ban will take place in Europe and has also been proposed in California. Car companies will need to find alternative materials for exterior protection. In other news, researchers have developed a heat-resistant ceramic ink that can be used to mark metal components in the automotive industry. This ink allows for the detection of production glitches and can improve the efficiency of process chains. Additionally, materials science could help reduce energy consumption in data centers, and a new laser-based method has been developed to discover puncture-resistant materials. Finally, scientists have observed metals healing themselves, which could have significant implications for engineering. [Extracted from the article]

Within this work, ink formulations based on polyorganosilazane (OPSZ) and divinylbenzene (DVB) were developed to be processed by inkjet printing. The formulations were studied regarding their rheological, structural, and thermal properties. The rheological results show that the new formulations meet the requirements of the inkjet printer by showing both low viscosity (below 20 mPa∙s at printing temperature) and Newtonian flow behavior even at high shear rates. Additionally, the inks have surface tensions in the range of 21 to 26 mN/m2. First, printing experiments of single layers were successfully conducted and show that the developed formulations can be processed by inkjet printing. The inks were crosslinked by UV light and then pyrolyzed at 1100 °C resulting in a ceramic yield between 75 and 42%, depending on the ink formulation. The crosslinking behavior was studied via FTIR spectroscopy, and the results reveal that crosslinking occurs mainly via free-radical polymerization of the vinyl group. Furthermore, the results indicate that silicon carbonitride (SiCN) was formed after the pyrolysis. The results of the electrical properties of the amorphous ceramics differ in dependence on the amount of DVB in the formulation. A maximum electrical conductivity of 1.2 S/cm−1 was observed for a UV-cured sample with a high amount of DVB pyrolyzed at 1100 °C. The generation in electrical conductivity is given by the formation of free carbon derived most likely by DVB. [ABSTRACT FROM AUTHOR]

A flexible printing electronical membrane is an electron equipment made by precisely spraying conductive metal ink such as silver on a soft membrane substrate. With its advantages of light weight and flexibility, it can adapt to changing working environments and is widely used in aerospace, wearable electronics and other fields. Nevertheless, during the manufacturing preparation of roll-to-roll printing membranes, the high-speed movement of printing electronical membranes under tension is affected by the impact of hot air from the drying oven and the electrostatic interference generated by friction in transmission, which restricts the overprint accuracy and preparation velocity of flexible electronical membranes. To address this issue, the nonlinear forced vibrational characteristics of a traveling flexible printing electronical membrane on temperature coupling subjected to nonlinear electrostatic force were investigated. The roll-to-roll printed intelligent RFID electron membrane is the research target. On the basis of the energy approach and the heat conduction equation considering the effect of deformation, the nonlinear vibrational equations of an axially traveling flexible printing electronical membrane coupled with temperature under the function of nonlinear electrostatical excitation force were derived. The Bubnov–Galerkin algorithm was applied to discretize the vibration partial differential equations; by making full use of the quartic Runge–Kutta numerical algorithm to calculate the approximate solution of equations, the phase portraits, Poincaré maps, time history diagrams, power spectra, and bifurcation plots of the nonlinear vibrations of the traveling printing electronical membrane were used to explore the effects of movement velocities, electrostatical field, and thermal coupling coefficients. The findings obtained the stable working domain and the divergence instability domain of the traveling flexible printing electronic membrane, which provided a theory fundamental for enhancing the stable craft of a printing electronical membrane. [ABSTRACT FROM AUTHOR]

Direct ink write deposition facilitates line‐by‐line extrusion of inks spanning wide viscoelastic ranges. Following deposition, post processing technologies permit tuning of the extrudate's material property characteristics—ultraviolet (UV) irradiation, facilitating the photopolymerization of UV‐reactive catalyst solutions, permits targeted modification of the extrudate's microstructure and in situ tuning of extrudate macrostructure. This report analyzes the morphological, rheological, and microstructural property relationships governing the printability, and processivity, of extruded UV‐curable resin inks for delineation of sufficiency and optimization of ink printability utilizing direct ink write technologies. A design‐of‐experiments approach is implemented to quantify significance regarding an extrudate's dimensional response to extrusion parameter variation and in situ processing parameters, identifying proportionally of nozzle velocity, nozzle height, and UV irradiation exposure with extrudate aspect ratio, reflected by respective maximum extrudate aspect ratio increases of 158% and 109%, regarding 121 and 123K resin inks. Finally, the relationship between extrudate morphology and microstructure variation was assessed via dielectric cure monitoring, whereby an extrudate's ion viscosity was calculated in relation to its rheological modulus, reflecting the relationship between an extrudate's morphology, rheological response, and printability, regarding its microstructural variation. [ABSTRACT FROM AUTHOR]

Nickel oxide (NiO) is a p-type material with a wide bandgap of 3.6 to 4 eV, and graphene is a zero-bandgap material. When the two materials are combined to form a composite, their structural, optical, and electrical properties are enhanced. This work presents the formulation of nickel oxide (NiO)–graphene composite ink (with ethylene glycol as a solvent) for the fabrication of thin-film electrodes using a direct ink writing technique. NiO is used in nanopowder form, which is prepared via a wet-chemical approach. NiO ink is prepared in three different concentrations of 40 mg/ml (N1), 60 mg/ml (N2), and 70 mg/ml (N3). Graphene ink (G) is also prepared in concentrations of 0.5 mg/ml (G1), 1 mg/ml (G2), and 2 mg/ml (G3). Among the pure NiO inks, it was observed that low resistance and uniform printing were obtained for N2. Therefore, N2 is mixed with different concentrations of graphene to form the composite ink, which is further printed on the substrates. The rheological properties of all the formulated inks are measured. An extrusion-based direct-write system is employed for printing the inks on a glass substrate. The printed samples are characterized before and after annealing at 250°C for 2 h. The resistance of the composite ink (N2G1) is decreased by 53% in comparison with the pure NiO ink (N2). As the conductivity of the composite ink thin film is in the range of MΩ, they could find application in the field of gas sensing and thermistors. [ABSTRACT FROM AUTHOR]