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Microfluidic chips have shown their potential for applications in fields such as chemistry and biology, and 3D printing is increasingly utilized as the fabrication method for microfluidic chips. To address key issues such as the long printing time for conventional 3D printing of a single chip and the demand for rapid response in individualized microfluidic chip customization, we have optimized the use of DLP (digital light processing) technology, which offers faster printing speeds due to its surface exposure method. In this study, we specifically focused on developing a fast-manufacturing process for directly printing microfluidic chips, addressing the high cost of traditional microfabrication processes and the lengthy production times associated with other 3D printing methods for microfluidic chips. Based on the designed three-dimensional chip model, we utilized a DLP-based printer to directly print two-dimensional and three-dimensional microfluidic chips with photosensitive resin. To overcome the challenge of clogging in printing microchannels, we proposed a printing method that combined an open-channel design with transparent adhesive tape sealing. This method enables the rapid printing of microfluidic chips with complex and intricate microstructures. This research provides a crucial foundation for the development of microfluidic chips in biomedical research. [ABSTRACT FROM AUTHOR]

We investigated a potential of femtosecond laser sintering of silicon carbide (SiC) using the nanoparticles in air. A SiC nanoparticle ink including polyvinylpyrrolidone and ethylene glycol exhibited intense absorption by SiC nanoparticles at the wavelength of 780 nm. The whole of the sintered film patterns from the surface to the bottom underwent significant oxidation at a scanning speed of 1 mm/s, suggesting that the excessive energy irradiation generated silicon oxides. In contrast, the patterns fabricated by laser scanning at a raster pitch of 30 µm at which a sintered area was observed at a scanning speed of 5 mm/s, exhibited no significant difference in oxidation of the raw SiC nanoparticles except for the surfaces from 1.72 µm. These results indicate that the irradiation of femtosecond laser pulses generated the sintered SiC patterns without additional atmospheric oxidation of the raw materials because of its low heat accumulation. In additions, the dispersant of polyvinylpyrrolidone and ethylene glycol did not affect the sintering by an X-ray photoelectron spectroscopy. This vacuum-free direct printing technique has the potential for additive manufacturing. [ABSTRACT FROM AUTHOR]

Hydrogel materials endow the flat optics platform with active tuning capability, owing to their remarkable humidity‐responsive swelling behavior. Despite recent advances in hydrogel‐based devices for spectral tuning, their complex patterning processing and limited functionality obstruct them from practical applications. Herein, a single‐step direct‐printing technique is originally demonstrated with an active hydrogel material platform for realizing unprecedented multi‐field full‐color display dynamics. Through exploring the dose‐induced shrinkage on polyvinyl alcohol, the stepwise hydrogel nanocavities sandwiched by ultrathin metallic films can be directly printed by grayscale e‐beam lithography. Due to the tunable structural coloration from hydrogel nanocavity scaling, multi‐functionalities are successfully created for optical concealment, dynamic coloring, and dynamic full‐color holography. By encoding the cavity‐dependent transmission phase into the direct‐printed hydrogel platform, it originally enables the projected full‐color holographic dynamics in real‐time by simply exhalation, beyond the static holographic display or monochromatic holographic switching. The proposed active displays can rapidly respond to the surrounding humidity change at a millisecond‐level (< 150 ms). Such a direct‐printing strategy for hydrogel nanocavity represents a critical advance toward the unprecedented dynamic full‐color display, and suggests promising applications in optical security, gas sensing, multispectral imaging, full‐color holography, and next‐generation display techniques. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) is widely used to create 3D models for medical purposes. However, the AM processing chain for medical applications is complex and poses a relatively high technical barrier, particularly when designing and printing multi-material or porous structures. To streamline the processing chain and improve the efficiency of designing and printing porous medical models, a new method is proposed to skip 3D model reconstruction and costly slicing. It allows the direct design of parametric toolpath slices using CT images to print medical models with controllable porosities. This brings a significant potential shift in the current medical AM paradigm. [ABSTRACT FROM AUTHOR]

In this study, an efficient hierarchical Co–Pi cluster/Fe2O3 nanorod/fluorine-doped tin oxide (FTO) micropillar three-dimensional (3D) branched photoanode was designed for enhanced photoelectrochemical performance. A periodic array of FTO micropillars, which acts as a highly conductive "host" framework for uniform light scattering and provides an extremely enlarged active area, was fabricated by direct printing and mist-chemical vapor deposition (CVD). Fe2O3 nanorods that act as light absorber "guest" materials and Co–Pi clusters that give rise to random light scattering were synthesized via a hydrothermal reaction and photoassisted electrodeposition, respectively. The hierarchical 3D branched photoanode exhibited enhanced light absorption efficiency because of multiple light scattering, which was a combination of uniform light scattering from the periodic FTO micropillars and random light scattering from the Fe2O3 nanorods. Additionally, the large surface area of the 3D FTO micropillar, together with the surface area provided by the one-dimensional Fe2O3 nanorods, contributed to a remarkable increase in the specific area of the photoanode. Because of these enhancements and further improvements facilitated by decoration with a Co–Pi catalyst that enhanced water oxidation, the 3D branched Fe2O3 photoanode achieved a photocurrent density of 1.51 mA cm−2 at 1.23 VRHE, which was 5.2 times higher than that generated by the non-decorated flat Fe2O3 photoanode. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) water splitting, which harnesses solar radiation (an infinite energy source) for clean hydrogen production without carbon-dioxide emissions, is an ideal eco-friendly energy technology. The core reactions in PEC water splitting, involving the oxidation and reduction of water, are driven by electron–hole pairs generated through solar energy absorption. Consequently, the light-absorption efficiency emerges as a critical parameter in PEC devices. Conventional thin-film-type photoanodes, however, grapple with limited absorption due to their high reflectance, hindering absorption and carrier separation efficiency. Conversely, moth-eye-structured photoanodes exhibit an anti-reflection effect stemming from their subwavelength structure, markedly enhancing light-absorption efficiency. In this study, we present the design and fabrication of a densely packed moth-eye-structured bismuth vanadate (BiVO 4) (M-BVO) photoanode, which is engineered to possess superior light absorption properties. The photoanode was fabricated via direct printing, electron-beam evaporation, and Vanadium calcination processes. The light absorption of the resulting M-BVO photoanode increased to approximately 92 % within the 300–500 nm wavelength range, with the absorption efficiency (η abs) surging to 82.9 %. This represents a 23.5 % enhancement compared to its flat BiVO 4 counterparts. Impressively, the photocurrent density of M-BVO reached 2.98 mA cm−2 at 1.23 V RHE , 37.6 % higher than that of flat BiVO 4. These results indicate that the PEC efficiency can be significantly increased through moth-eye structuring, emphasizing the indispensable role of nanostructure research in the manufacture of high-efficiency photoanodes. A densely packed moth-eye-structured BiVO 4 photoanode was realized through simple processes of e-beam evaporation and direct printing. These enhanced optical properties improve PEC efficiency by increasing the light absorption efficiency. [Display omitted] • Densely packed moth-eye-structured BiVO 4 photoanode, fabricated via direct printing and e-beam evaporation, achieved a photocurrent density of 2.98 mA cm-2 and 82.9% absorption efficiency, significantly outperforming flat photoanodes. [ABSTRACT FROM AUTHOR]

Flexible and soft bioelectronics used on skin tissue have attracted attention for the monitoring of human health. In addition to typical metal-based rigid electronics, soft polymeric materials, particularly conductive hydrogels, have been actively developed to fabricate biocompatible electrical circuits with a mechanical modulus similar to biological tissues. Although such conductive hydrogels can be wearable or implantable in vivo without any tissue damage, there are still challenges to directly writing complex circuits on the skin due to its low tissue adhesion and heterogeneous mechanical properties. Herein, we report cellulose-based conductive hydrogel inks exhibiting strong tissue adhesion and injectability for further on-skin direct printing. The hydrogels consisting of carboxymethyl cellulose, tannic acid, and metal ions (e.g., HAuCl4) were crosslinked via multiple hydrogen bonds between the cellulose backbone and tannic acid and metal-phenol coordinate network. Owing to this reversible non-covalent crosslinking, the hydrogels showed self-healing properties and reversible conductivity under cyclic strain from 0 to 400%, as well as printability on the skin tissue. In particular, the on-skin electronic circuit printed using the hydrogel ink maintained a continuous electrical flow under skin deformation, such as bending and twisting, and at high relative humidity of 90%. These printable and conductive hydrogels are promising for implementing structurally complicated bioelectronics and wearable textiles. [ABSTRACT FROM AUTHOR]

Additive fabrication use for the development of sensing devices with complex geometries is increasing constantly. Novel polymer-based materials with conductive properties are among the most investigated materials for soft electronics. In this study, we developed a fully additive-fabricated flexible contact pressure sensor using multi-material printing. The sensing part is a three-dimensional disc printed by extruding a multi-walled carbon nanotube-polymer composite using a laboratory-scale direct ink writing (DIW) process. The DIW process repeatability was studied, and it shows highly repeatable printing characteristics of the sensors. The pressure sensor response under compressive load was also investigated, showing that the sensor exhibited high sensitivity over a wide range of pressure and sensitivity to small increments of compressive force. The dynamic response of the sensor was also studied for different loading conditions where it showed good dynamic characteristics, and the sensor response-recovery time was 0.02 s. [ABSTRACT FROM AUTHOR]

Flexible optoelectronics have fully demonstrated their transformative roles in various fields, but their fabrication and application have been limited by complex processes. Liquid metals (LMs) are promising to be ideal raw materials for making flexible optoelectronics due to their extraordinary fluidity and printability. Herein, we propose a painting-modifying strategy based on solution processability for directly printing out fluorescent flexible optoelectronics from LMs via surface modification. The LMs of eGaIn, which were obtained by the mixing of gallium with indium metal spheres, were used as ink to paint high-finesse patterns on flexible substrates. Through introducing surface modification of LMs, the gallium atom on the surface of the LMs was directly transformed into the composite fluorescent functional layers of GaO(OH) and GaN after being modified with an ammonia aqueous solution. Owing to painting, this strategy is not limited by any curved surfaces, shapes, or facilities and has excellent adaptability. Particularly, the fluorescent layers were obtained through a spontaneous, instantaneous, and solution-processable process that is environmentally friendly, easy to administrate, recyclable, and adjustable. The present finding breaks through the limitations of LMs in making flexible optoelectronics and provides strategies for addressing severe challenges facing existing materials and flexible optoelectronics. This method is expected to be very useful for fabricating flexible lights, transformable displays, intelligent anticounterfeiting devices, skin-inspired optoelectronics, and chameleon-biomimetic soft robots in the coming time.

Directly written circuits on polymeric housings can reduce weight and enhance flexibility due to the wiring of electronic devices and systems in automotive and aerospace parts. These circuits must conform to a variety of geometries while maintaining electrical conductivity after deformations. To address these challenges, a hybrid copper-based ink has been developed capable of self-healing. Low melting temperature metals such as indium can work as a self-healing agent in response to deformational processes such as thermoforming. A new generation of devices is conceptualized utilizing printable hybrid copper-based ink, sintered and healed within a few milliseconds via intense pulsed light (IPL). [ABSTRACT FROM AUTHOR]

Attempts were made to find a more environmentally friendly technique for the printing of polyester (PET ) fabric, acting as an alternative to a usual disperse dye direct-printing process by using a plenty of water and salt and producing effluent contaminants. The low-emission printing technique includes the recipe containing disperse dye paste, synthetic thickener and the water-based silicone-modified acrylate and high-temperature curing process. The water-based silicone-modified acrylate for adhesive coating of polyester (PET) fibres was synthesized using butyl acrylate (BA), eight four methyl siloxane (D4), acrylonitrile (AN), styrene (St), methyl acrylic acid (MAA) and N-methylol acrylamide (NMA).The results showed that the silicone-modified acrylate adhesive could increase the percentages of dye fixation and the colour strength. The superior colour fastness (≥level 4) with the low-emission printing process was realized. The wastewater stream produced by the technique had a residual dye concentration of 2.62 mg/L, which was reduced by approximately 19 times that produced by traditional direct printing. The effluent wastewater drainage was reduced by 76.9%.

In this study, an efficient hierarchical Co–Pi cluster/Fe2O3 nanorod/fluorine-doped tin oxide (FTO) micropillar three-dimensional (3D) branched photoanode was designed for enhanced photoelectrochemical performance. A periodic array of FTO micropillars, which acts as a highly conductive “host” framework for uniform light scattering and provides an extremely enlarged active area, was fabricated by direct printing and mist-chemical vapor deposition (CVD). Fe2O3 nanorods that act as light absorber “guest” materials and Co–Pi clusters that give rise to random light scattering were synthesized via a hydrothermal reaction and photoassisted electrodeposition, respectively. The hierarchical 3D branched photoanode exhibited enhanced light absorption efficiency because of multiple light scattering, which was a combination of uniform light scattering from the periodic FTO micropillars and random light scattering from the Fe2O3 nanorods. Additionally, the large surface area of the 3D FTO micropillar, together with the surface area provided by the one-dimensional Fe2O3 nanorods, contributed to a remarkable increase in the specific area of the photoanode. Because of these enhancements and further improvements facilitated by decoration with a Co–Pi catalyst that enhanced water oxidation, the 3D branched Fe2O3 photoanode achieved a photocurrent density of 1.51 mA cm−2 at 1.23 VRHE, which was 5.2 times higher than that generated by the non-decorated flat Fe2O3 photoanode.

Facile printing process for solution‐processed metal oxide thin‐film transistors (TFT) is a promising technology to provide various human interactive devices such as flexible displays and wearable sensors. A simple spontaneous direct printing approach for the electrode (ITO) with directly patterned metal oxide semiconductors (IZO) will be presented. [ABSTRACT FROM AUTHOR]

Abstract Gravure printing is a promising technique for large-scale printed electronics. However, gravure printing of silver nanowires (AgNWs) so far has been limited in terms of resolution and electrical conductivity. In this study, gravure printing of water-based AgNW ink on a flexible substrate is demonstrated. By tailoring the ink properties, printing conditions and post-printing treatment, gravure printing enables printing of high-resolution, highly conductive AgNW patterns in large areas, with resolution as fine as 50 µm and conductivity as high as 5.34 × 104 S cm−1. The printed AgNW patterns on the flexible substrate show excellent flexibility under repeated bending. All these characteristics demonstrate the excellent potential of gravure printing of AgNWs for developing large-area flexible electronics.

• A motheye-structured photoanode for water splitting was designed and fabricated. • The motheye-patterned gap-plasmon structure maximized solar absorption. • A current density of 1.48 mA/cm2 was obtained with a thin layer of BiVO4 (200 nm). Bismuth vanadate (BiVO 4) is one of the most promising materials used in photoelectrochemical cells (PEC cells), which are significant generators of clean energy. As with many promising materials used as photoanodes, the main problem limiting the efficiency of BiVO 4 -based photoanodes is the trade-off between their large light penetration depth and small diffusion length. To reduce this gap, various methods have been investigated to improve the absorption efficiency of ultra-thin BiVO 4 layers, including template-assisted nanostructuring. In this study, we have implemented a densely packed sub-wavelength-scale nanocone array inspired by the motheye morphology using a direct printing method. Subsequently, we fabricated a series of triple-deck hierarchical photoanodes using a motheye template via the successive deposition of Au, SnO 2 , and BiVO 4. The fabricated motheye structures exhibit a gradual change in their refractive index, which is excellent for reducing the reflection of high refractive index materials. In addition, the synergy between the light trapping effects of the nanocone array and gap-plasmon structure (reflector/spacer/antenna) maximizes the absorption of incident solar light. Due to this enhancement, a current density of 1.48 mA/cm2 was obtained using a thin layer of BiVO 4 (200 nm) at 1.23 V vs. RHE under a simulated solar light (AM 1.5G). Our results can be applied toward many promising candidate materials used for photoanode and optoelectronic devices, where poor electronic properties and high reflectivity limit the absorption and power generation efficiencies. [ABSTRACT FROM AUTHOR]

The performance of solar cells is determined by three factors: the open-circuit voltage (VOC), short-circuit current density (JSC), and fill factor (FF). The VOC and FF are determined by the material bandgap and the series/shunt resistance, respectively. However, JSC is determined by the amount of incident light in addition to the bandgap of the material. In this study, a moth-eye pattern was formed on a glass surface via direct printing to increase the amount of incident light and thus increase JSC. The moth-eye pattern is a typical antireflection pattern that reduces the reflection by gradually increasing the refractive index. A flat perovskite solar cell (F-PSC) and a moth-eye patterned perovskite solar cell (M-PSC) had JSC values of 23.70 and 25.50 mA/cm2, respectively. The power-conversion efficiencies of the F-PSC and M-PSC were 19.81% and 21.77%, respectively. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have been in the spotlight as a promising next-generation solar cell. With the tremendous development of power conversion efficiency (PCE) over the past decades, a considerable amount of research has focused on semi-transparent perovskite solar cells for applications. However, the short-circuit current density (J SC) greatly decreases in semi-transparent PSCs with an increase in transmittance, and this results in a significant decrease in PCE. In this study, semi-transparent PSCs were fabricated by controlling the absorption layer thickness and aperture ratio using a 3D-structured FTO manufactured via processes that can work large areas (direct printing and mist-CVD). This strategy has an advantage in that the aperture ratio (transmission/entire area) can be controlled easily by adjusting pattern specification. The effect of a 3D-structured FTO enhanced the diffuse transmittance and shortened the carrier travel distance; further, it minimized the decrease in PCE because of an increase in transmittance. Our fully semi-transparent PSCs (F–PSCs) with the ITO cathode achieved a PCE of 12.0 %–14.6 %, and an average visible transmittance (AVT) of 13.4 %–17.0 %. These results demonstrate that the parameter of semi-transparent PSCs (transmittance and PCE) can be easily tailored to the application by controlling the specification of the pattern. [ABSTRACT FROM AUTHOR]

Flexible electronics are showing a promising potential as the next technology revolution in electronics. Flexible tactile sensors, in particular, are getting a lot of attention and have been rapidly developing in the last few years. This is due, inter alia, to the large expansion of the wearable electronic market, flexible displays and the robotic applications where robots are developed to better interact with the external environment through physical contact via the use of tactile sensors. 3D printing technology is being more applied to develop electronic devices giving its numerous advantages. In this regard, the present work reports an improved strain sensor in terms of low and stable electrical resistance over a considerable period of time. The structure of the sensor consists of an elastomeric composite material composed of polydimethylsiloxane (PDMS) and a multi-walled carbon nanotubes (MWCNTs) conductive line deposited using the Direct-Write technique in between two elastomer substrates (PDMS). The developed sensor was able to display significant stability and relatively low resistance. The stability of the resistance throughout a period of 10 days, allowed the study of the dispensing parameters (such as the feed rate and the dispensing pressure of the conductive nanocomposite) influencing the dimensional characteristics (such as the dispensed line width and height). A numerical representation of the relation between the dispensing parameters and the obtained characteristics of the conductive line is presented. [ABSTRACT FROM AUTHOR]

Bioprinting techniques can be used for the in vitro fabrication of functional complex bio-structures. Thus, extensive research is being carried on the use of various techniques for the development of 3D cellular structures. This article focuses on direct writing techniques commonly used for the fabrication of cell structures. Three different types of bioprinting techniques are depicted: Laser-based bioprinting, ink-jet bioprinting and extrusion bioprinting. Further on, a special reference is made to the use of the bioprinting techniques for the fabrication of 2D and 3D liver model structures and liver on chip platforms. The field of liver tissue engineering has been rapidly developed, and a wide range of materials can be used for building novel functional liver structures. The focus on liver is due to its importance as one of the most critical organs on which to test new pharmaceuticals, as it is involved in many metabolic and detoxification processes, and the toxicity of the liver is often the cause of drug rejection. [ABSTRACT FROM AUTHOR]

Abstract Strain sensors with high sensitivity and large stretchability are of interest in various engineering fields. Here, directly printed stretchable strain sensors with great sensitivity and high durability was fabricated using aerodynamically focused nanomaterials (AFN) printing system. Specifically, microscale porous conductive patterns composed of silver nanoparticles (AgNPs) and multi-walled carbon nanotubes (MWCNTs) composites are printed onto polydimethylsiloxane (PDMS) for stretchable strain sensor. Printing mechanisms of AFN printing system for nanocomposites onto flexible substrates were demonstrated and experimentally validated. The printed nanocomposites strain sensor exhibits high sensitivity and wide measurable range with high mechanical stability. It shows gauge factor (GF) of 58.7, maximum strain limit of 74% and variance in peak resistance is under 5% peak during 1000 times loading-unlading life cycle evaluation test. Sensing mechanisms were analysed and explained statistically using bivariate probit models. Moreover, we also showed that sensitivity and stretchability of printed strain sensors can be controlled by regulation of AFN printing process parameter and nanocomposite composition ratio. [ABSTRACT FROM AUTHOR]

Bioprinting techniques can be used for the in vitro fabrication of functional complex bio-structures. Thus, extensive research is being carried on the use of various techniques for the development of 3D cellular structures. This article focuses on direct writing techniques commonly used for the fabrication of cell structures. Three different types of bioprinting techniques are depicted: Laser-based bioprinting, ink-jet bioprinting and extrusion bioprinting. Further on, a special reference is made to the use of the bioprinting techniques for the fabrication of 2D and 3D liver model structures and liver on chip platforms. The field of liver tissue engineering has been rapidly developed, and a wide range of materials can be used for building novel functional liver structures. The focus on liver is due to its importance as one of the most critical organs on which to test new pharmaceuticals, as it is involved in many metabolic and detoxification processes, and the toxicity of the liver is often the cause of drug rejection.

This paper reveals new insights on how to achieve direct deposition of functional materials onto silicon wafers for cooling purposes. Manufacturing heat spreaders directly onto a microprocessor will negate the need for Thermal Interface Materials (TIMs) which often account for the highest resistances in a typical CPU thermal circuit. In this work we demonstrate that Cold Spray can be tailored to directly print onto a silicon wafer with a layered structure of aluminum, copper and diamond. The thermal performance of the copper/diamond coating was also separately measured using an in-house testing apparatus showing heat-transfer enhancements in agreement with theoretical predictions. [ABSTRACT FROM AUTHOR]

A newly developed nanoparticle printer is presented for high resolution pattering of conductive nanoparticles onto the carbon and glass fiber reinforced composites. The nanoparticles are aerodynamically focused to generate nanoparticle beam for high resolution patterns. The resulting conductive patterns are evaluated for the strain measurement of composites for structural health monitoring (SHM). A series of strain sensors are printed onto the composites and their performances are characterized in terms of gauge factor, measurable range, and etc. The presented work leverages the advanced techniques of process and part monitoring of composite manufacturing as well as for the SHM of the composite. [ABSTRACT FROM AUTHOR]

Micro- and nanoscale structures are of interest in various engineering fields due to their unique properties, such as hydrophobicity. In particular, micro/nano hierarchical structures have been investigated to promote surface hydrophobicity. Here, aerodynamically focused nanoparticle (AFN) printing was used for direct printing of superhydrophobic patterns. As AFN printing is a room-temperature direct printing technique, printed features have a hierarchical structure of two levels; nanoscale porous surface and microscale-printed patterns in three-dimensional structures. Moreover, because it is an additive fabrication technique, the printed pattern is repairable and can be reconfigured as desired. In this study, silver nanoparticles were used to implement a superhydrophobic pattern with a minimum width of tens of microns. The contact angle of water droplets was measured for various patterns, and the effects of nanoscale porosity and pattern interval were investigated. In addition, patterns were designed and fabricated to have anisotropic superhydrophobicity. The experimental results were analyzed and explained with the classical Wenzel and Cassie–Baxter models. [ABSTRACT FROM AUTHOR]

For the aim of enhancing adhesion of the solvent-free nanoparticle deposition at room temperature, we utilized a 355 nm nanosecond pulse laser to excite the airborne nanoparticles during the path of flight. The laser irradiation system was designed to only affect airborne nanoparticles, as preventing exposure on substrate. The calculated total energy of nanoparticles at impact point was increased compared to the deposition without irradiation. This result is due to the additional surface energy enhanced by laser activation. Deposition results with Al 2 O 3 and TiO 2 nanoparticles were evaluated. The hardness and porosity of deposited layer can be controlled by changing laser condition. [ABSTRACT FROM AUTHOR]

Stretchable electronics represent a new generation of electronics that utilize soft, deformable elastomers as the substrate or matrix instead of the traditional rigid printed circuit boards. As the most essential component of stretchable electronics, the conductors should meet the requirements for both high conductivity and the capability to maintain conductive under large deformations such as bending, twisting, stretching, and compressing. This review summarizes recent progresses in various aspects of this fascinating and challenging area, including materials for supporting elastomers and electrical conductors, unique designs and stretching mechanics, and the subtractive and additive patterning techniques. The applications are discussed along with functional devices based on these conductors. Finally, the review is concluded with the current limitations, challenges, and future directions of stretchable conductors. [ABSTRACT FROM AUTHOR]

Direct and discharge methods are two most frequently used fabric printing styles, with its advantages and disadvantages. Here the effect of direct and discharge style of printing on the mechanical properties of the dyed silk fabric has been studied in detail. Mulberry bivoltine raw silk woven fabric was used for these studies. The fabric was degummed, dyed using metal complex dye and printed by using direct and discharge styles of printing. The dyed (control) and printed samples were conditioned and analyzed for mechanical properties. It was found that the printing process affects some of the mechanical properties. Silk fabric printed by discharge method has shown substantial drop in both tensile and tear strength compared to the direct method. [ABSTRACT FROM AUTHOR]

We previously developed a method for producing highly conductive RuO 2 films using a solution-based process. In this paper, we describe the further development of this material to produce fine patterns for use in nano-sized devices through a newly developed direct imprinting process, named nano-Rheology Printing (n-RP). This process involves the fine patterning of the precursor gel by an imprinting process to generate fine solid patterns while avoiding potential pattern breakage during sintering. The pattern breaking is typically caused by the crystallization nature of an oxide material, which may become more prominent when the size is reduced to less than 100 nm. To solve this problem, we investigated the properties of the Ru–La system and observed that a small addition of La to Ru greatly improved the viscoelastic property of the gel without any noticeable reduction of conductivity. The Ru–La system also exhibited an amorphous state over a wide composition range, and thus the fine gel patterns produced by the imprinting process were resistant to breakage during sintering. These unique properties of the Ru–La system were thought to result from the molecular crystalline nature of the La gel. Based on the results, the n-RP method could successfully fabricate a fine line of the Ru 0.75 -La 0.25 O oxide with a width of 30 nm and with good conductivity. [ABSTRACT FROM AUTHOR]

In this study, a hydrogen silsesquioxane (HSQ) and zirconium oxide (ZrO, zirconia) nanoparticle composite was used for a nanopatterned roll stamp fabricated using the direct printing technique. HSQ, referred as a spin on glass (SOG) material have been used for direct printing process with polydimethylsiloxane mold. In order to enhance mechanical properties of SOG material without losing printable property, ZrO nanoparticles were dispersed with HSQ solution. After direct printing process of composite material, annealing process was done to convert polymeric HSQ structure into SiO in order to enhance mechanical properties. We evaluate the chemical, optical and mechanical properties of the HSQ/ZrO composite by FT-IR, a refractive index measurement, a nanoindentation test and a pencil adhesion test. At the mechanical property tests, the composite material shows a high hardness value and good adhesion properties with glass substrate. Considering the composite material properties, it is suitable for use as a master cylindrical stamp in a roll-to-roll process. [ABSTRACT FROM AUTHOR]