Inkjet Device Research Articles

Inkjet-based facile fabrication of a copper ferrocyanide-embedded magnetic alginate microadsorbent for highly enhanced cesium removal

For the first time, simple and facile fabrication of a magnetic alginate microadsorbent via piezoelectric inkjet technology was developed for the selective removal of 137Cs via magnetic separation. Through the ejection of an alginate solution containing potassium ferrocyanide and magnetic nanoparticles (MNPs) into a Cu2+ solution via an inkjet device, the fabrication of a copper ferrocyanide-embedded magnetic alginate microadsorbent (CuFC-MAM) with an average size of 39.38 μm was easily achieved in a one-pot fabrication process; here, the Cu2+ ions acted as both a cross-linker for the gelation of alginate and a Cu source for the in situ synthesis of CuFC with potassium ferrocyanide. The Cs adsorption behavior of CuFC-MAM was effectively fitted by the pseudo-second-order kinetic model and Langmuir isotherm. Owing to the increased specific surface area of CuFC-MAM, its pseudo-second-order rate constant and maximum adsorption capacity were 76.54 and 1.486 times greater than those of CuFC-embedded magnetic alginate macroadsorbents fabricated without inkjet devices. Compared with other Cs adsorbents, CuFC-MAM presented the highest maximum capacity and Kd value; these results were attributed to the high content of CuFC in CuFC-MAM (50.15%). In addition, our CuFC-MAM exhibited an excellent removal efficiency of radioactive Cs, exceeding 99% from seawater.

20‐5: Quantum Dots and Device Optimizations towards Ink Jet Printing Quantum Dots Light Emitting Diodes Displays

In this paper, we have meticulously refined both the quantum dot (QD) materials, particularly the blue variants, and the ink formulations to achieve aesthetically pleasing, high‐performance printing devices. Furthermore, in anticipation of future mass production challenges, we have tailored the quantum dot ligands and adopted surface passivation of zinc oxide nanoparticles, leveraging their inherent material properties. This innovation has culminated in remarkable enhancements for inkjet QLED device in long‐term storage stability and efficiency.

The Complexity of Colour/Textile Interaction in Digital Printing as an Integral Part of Environmental Design

Textile materials are an essential part of contemporary architecture, the environment, and urban spaces due to their unique appearance and qualities, as it is now possible to achieve both a structural function and an aesthetic quality with textiles. As colour is one of the most important characteristics of textile material, it is also important to understand the relationships between colour and textile material with different surface qualities. In order to explain the complexity of different textile materials and the appearance of colours, which consequently affects the colour properties, this paper analyses this phenomenon. The presented research analyses the dependence of the reproduction quality and colour appearance on fabrics of different construction and structural characteristics, i.e., the texture of the textile material, printed using digital inkjet technology. The aim of this work is to investigate the influence of various structural features of textiles on the colour appearance of digitally printed textile substrates, to monitor the quality of colour reproduction, and to analyse the behaviour of a reactive dye droplet on textile substrates. Printing of a particular shape was performed using a Dimatix Materials Printer DMP-2831 piezoelectric inkjet device (provided by the J. Stefan Institute, Ljubjana, Slovenia; manufactured by Fujifilm Dimatix Inc., 2230 Martin Avenue, Santa Clara, CA, USA). The behaviour of the ink delivered by the needle of the tensiometer DSA20E, Kruess GmbH (provided by the J. Stefan Institute, Ljubjana, Slovenia; manufactured by Kruess Scientific Instruments (Shanghai) Co., Ltd. Futong Dong Dajie 10 Baoneng Center, Tower B, Room 605 Chaoyang District, Beijing 100102, China), on the surface of the fabric was analysed. The samples were digitally printed on a Mimaki digital printer Tx2-1600 (provided by University of Ljubljana Faculty of Natural Science and Engineering, Slovenia EU; manufactured by Mimaki, 2182-3 Shigeno-Otsu, Tomi-city, Nagano, Japan), with reactive dyes, which were first pretreated in a bath with a specific solution. The statistical method of image analysis and microscopic imaging were used to obtain the characteristics of the porosity, texture, and roughness parameters. All results are presented from colouristic analysis based on the objectification of colour and colour differences. The objective values of the parameters of lightness (L*), chroma (C*), and hue (h°) show the significant influence of the structure and properties of the substrate on colour reproduction, and significant changes were obtained, which were confirmed by the evaluation of the colour differences. The results confirm the influence of the substrate structure on colour properties. Furthermore, it is essential to consider this complexity in the context of environmental colour design when utilising (coloured) textile installations/materials in architecture and urban spaces, i.e., in the environment.

On the dynamics of head-on collision of sessile droplets on the traveling substrate

In this work, the dynamics of the head-on collision of two sessile water droplets, namely the moving droplet and pinning droplet, on a traveling substrate was experimentally investigated. Unlike the traditional scenario of sessile droplets collision, the traveling substrate propelled the moving droplet attached to it to move at a certain speed. The results revealed that there are only two distinct regimes of collision consequences: coalescence without separation and separation with separation. A series of time-resolved photographic images mapping all the collision regimes in the parameter space of Capillary number and size ratio were used to identify the controlling factors for different collision results. The breakup of the receding meniscus in separation regime was discussed in detail as it is caused by the change of the droplet morphology. The findings indicated that the length of the receding meniscus played a significant role in the droplet impact dynamics, and when it exceeded about 8.2 mm, the receding meniscus broke up. Furthermore, it was demonstrated that the sum of the volume of initial pinning droplet’s receding meniscus and the volume of the moving droplet before collision is equal to the volume of the receding meniscus at its maximum length after collision. The critical Capillary number/size ratio for the transition between these two regimes was derived based on the volume principle before and after the collision. The model-predicated results show good agreement with the experiments. The findings could contribute to a better understanding of the droplet collision dynamics and the optimization of the anti-icing, self-cleaning and inkjet printing devices.

Inkjet-Based Intracellular Delivery System that Effectively Utilizes Cell-Penetrating Peptides for Cytosolic Introduction of Biomacromolecules through the Cell Membrane.

In the drug delivery system, the cytosolic delivery of biofunctional molecules such as enzymes and genes must achieve sophisticated activities in cells, and microinjection and electroporation systems are typically used as experimental techniques. These methods are highly reliable, and they have high intracellular transduction efficacy. However, a high degree of proficiency is necessary, and induced cytotoxicity is considered as a technical problem. In this research, a new intracellular introduction technology was developed through the cell membrane using an inkjet device and cell-penetrating peptides (CPPs). Using the inkjet system, the droplet volume, droplet velocity, and dropping position can be accurately controlled, and minute samples (up to 30 pL/shot) can be carried out by direct administration. In addition, CPPs, which have excellent cell membrane penetration functions, can deliver high-molecular-weight drugs and nanoparticles that are difficult to penetrate through the cell membrane. By using the inkjet system, the CPPs with biofunctional cargo, including peptides, proteins such as antibodies, and exosomes, could be accurately delivered to cells, and efficient cytosolic transduction was confirmed.

Absorption of millimeter- and micrometer-sized droplets on nylon powder

Absorption of droplet by the powder media is a ubiquitous phenomenon in many natural and engineering processes, in which the diameter of droplets ranges from tens of micrometers (μm) to a few millimeters (mm) depending on the specific condition. In this study, we investigate the absorption process following the impact of the droplet with radii varying from mm- to μm-scale on nylon powder substrate. The fluid properties are varied by mixing the deionized water with isopropyl alcohol at different volume ratios. A syringe pipette tip is used to generate droplets of diameter ranging from 2.08 to 2.30 mm, whereas a drop-on-demand inkjet device is used to dispense droplets of diameter ranging from 88 to 140 μm. The absorption process of the single droplet is captured by a high-speed imaging system. We find that for mm- and μm-droplets, there exists different critical surface tension below which the imbibition into the nylon powder can occur. With the proposed nondimensionalization process, the scattered data of dimensionless absorbed volume V and dimensionless time τ for different fluids generally collapse into a power law relation V ~ τα, where the exponent α for mm-sized and μm-sized droplets is 0.856 and 0.518, respectively. The experimental data of μm droplets generally agree with the prediction of the Washburn equation and diffusion-type equation for the unidirectional capillary flow, i.e., V ~ τ0.5. However, the results of mm-droplets favor more the prediction of the 3D radial flow (i.e., a hemispherically advancing infiltration front inside the powder), V ~ τ.

Polymer Solution With Very Low Relaxation Time: A Combined Numerical-Experimental Determination Strategy

Abstract For very low relaxation time (i.e., lesser than a microsecond), viscoelastic fluid experimental determination is difficult, if not impossible. In this work, the relaxation time measurement of a weakly elastic polymer solution, too low to be measured using classical rheometry techniques, is assessed using a mixed experimental-numerical strategy. First the fluid is rheologically assessed, by measuring its shear viscosity, surface tension, and density. Then the relaxation time is determined by comparing the jetting of polymer solution from a continuous ink-jet (CIJ) device, experimentally and numerically. The numerical approach is first validated using test cases, and a viscoelastic Oldroyd-B model is used to model the experimental solution. The relaxation time is then a parameter allowing us to fit numerical simulation onto experimental results. This mixed strategy is particularly convenient for weakly elastic solution for which physical parameters cannot be measured using an experimental rheometry setup.

A Machine Learning and Computer Vision Approach to Rapidly Optimize Multiscale Droplet Generation.

Generating droplets from a continuous stream of fluid requires precise tuning of a device to find optimized control parameter conditions. It is analytically intractable to compute the necessary control parameter values of a droplet-generating device that produces optimized droplets. Furthermore, as the length scale of the fluid flow changes, the formation physics and optimized conditions that induce flow decomposition into droplets also change. Hence, a single proportional integral derivative controller is too inflexible to optimize devices of different length scales or different control parameters, while classification machine learning techniques take days to train and require millions of droplet images. Therefore, the question is posed, can a single method be created that universally optimizes multiple length-scale droplets using only a few data points and is faster than previous approaches? In this paper, a Bayesian optimization and computer vision feedback loop is designed to quickly and reliably discover the control parameter values that generate optimized droplets within different length-scale devices. This method is demonstrated to converge on optimum parameter values using 60 images in only 2.3 h, 30× faster than previous approaches. Model implementation is demonstrated for two different length-scale devices: a milliscale inkjet device and a microfluidics device.

To calculate the axial dimensions of inkjet devices for hydraulic transport of sand and gravel materials

The article presents the results of the dredger in a deep deposit of sand and gravel materials. It was found that when the diameter of the suction pipe exceeds the diameter of the inlet mixing chamber by 150 mm, the actual pressure from the ejector does not exceed one meter, and with an increase in the supply of the suction pump as a result of a sharp jump in hydraulic resistance, the vacuum is disrupted. It was also found that the effect on the calculated compression ratio of the jet apparatus increases with an increase in the injection coefficient and the input velocity of the injected stream.

Ink Formulation and Optimum Surface Condition for a Printed Organic Light-Emitting Diode with High Boiling Point and Surface Tension Solvents

Ink formulation with the benzoate-type solvent mixture was designed to provide a mismatch in the surface tension, boiling point, and viscosity toward a stable jet printing on organic light-emitting diode (OLED) pixel pattern cell. Compared with a single component solvent ink, the mixtures showed smoother surface roughness and uniform line printed, while the dried film roughness was further improved by solvent-vapor annealing. Inkjet OLEDs on the 60 to 80 μm-scale pixels were fabricated, and the luminous quantum efficiency behavior of the printed OLEDs were characterized in terms of structural perfection of patterns and in-pixel coverage for different bank boundaries. With the optimum printing recipe and pattern-receptor surface condition, an external quantum efficiency of inkjet device was more than 82% of the value for spin-coating reference.

Inkjet polarography

A single nozzle piezoelectric inkjet device was introduced for polarography using a dropping carbon fluid electrode (DCFE). The viscosity of the carbon fluid prepared by mixing a spherical graphite powder and a perfluoroalkane oil was low enough for it to be ejected by the inkjet system. The periodic renewal of the DCFE was achieved at a frequency of 1 Hz with a constant droplet size (about 2 mm). A polarogram of ferrocenecarboxylate with a limiting current was observed.

Plasma-assisted synthesis of size-controlled monodisperse submicron gold particles using inkjet droplets

In this study, we synthesized gold spheroidized particles with sub-micrometer diameters via atmospheric-pressure plasma-assisted processing with inkjet droplets. Microdroplets of chloroauric acid (HAuCl4) solution were generated by an inkjet device with high reproducibility and exposed to radio frequency plasma. The synthesized sub-micrometer gold particles have a very narrow size distribution (3%–9% standard deviation), and their diameters can be controlled in the 0.3–0.6 μm range by adjusting the concentration of the solution.

Design and Structure Simulation Analysis of Sand-mold Inkjet Printing Device

Ink-jet printing technology is a digital high-efficiency forming technology that can realize the rapid manufacturing of sand mold for foundry. This paper designs a low-cost, high-reliability ink-jet printing device based on the sand-mold inkjet printing process, and uses ANSYS finite element analysis software to carry out static analysis and modal analysis for its main frame. The analysis results show that the main frame has good rigidity and high strength, there will be no large deformation and resonance in frame under the working conditions, which can meet the requirements of sand-type inkjet printing devices.

On the discrimination of inkjet, laser and photocopier printed documents using Raman spectroscopy and chemometrics: Application in forensic science

The potential of Raman spectroscopy combined with chemometrics has led to the development of rapid and non-destructive discrimination of inkjet, laser and photocopier printed documents. The present study is a novel approach to determine the source of origin of unknown printed documents based on its classification into laser or others (inkjet or photocopier) devices. We report the first ever use of Raman Spectroscopy combined with the Principal Component Analysis (PCA) and Partial Least Squares Discriminant Analysis (PLS-DA) to differentiate 387 samples (90 laser, 163 ink-jet, 134 photocopier) of printed document samples. Preliminary assessment through visual inspection of Raman spectra revealed the presence of C–C (aliphatic), aromatic bond and titanium dioxide in all toner samples. Comparison through spectral library of RS identified pigment carbon black (CI-77266) for laser and inkjet printout samples whilst pigment violet 19 (CI-73900) was found in photocopier samples. The unsupervised PCA correctly segregated the samples into 3 clusters and the supervised PLS-DA correctly classified them into three classes. A total of fifteen (15) unknown printed samples were correctly assigned to their source via the trained PLS-DA model. The chemometric approach used in this study showed a potential for the classification and individualisation of printed documents that can be applied to real forensic casework when a document is recovered from a crime scene during forensic investigation.

Interfaces and pattern resolution of inkjet-printed organic light-emitting diodes with a novel hole transport layer

In this paper, the effects of the combination of solvents on the uniformity of a dried emitting layer and on device performance were studied. Green emitter inks with various solvents were prepared, and it was seen that good film uniformity of printed layers could be obtained with a solvent mixture with different boiling points, which reduced the coffee ring effect on a dried surface. During the inkjet process, the drop injection condition aiming was also controlled for better drop-to-drop spacing and reduction of the line-edge roughness. Printed patterns of a small molecular/polymer hybrid emitting layer, composed of the chlorobenzene-dichlorobenzene solvent mixture, showed significantly reduced roughness of the microscopic surface and improved efficiency of the inkjet device, at levels nearly comparable to those of spin-coated patterns. A suitable hole transport layer (HTL) was also further developed as an interfacial material, prior to the solution processing of the emitter. The cross-linkable HTL was composed of triphenylamine as the cross-linking unit and a fluorene-based compound. At the optimized condition of the solvent formulation, printed droplets within 100 µm× 300 µm pixels formed a uniform stripe without remarkable coffee-ring defects and line-edge surface roughness.

Synthesis and Research of Rare Earth Nanocrystal Luminescent Properties for Security Labels Using the Electrohydrodynamic Printing Technique

YVO4:Eu3+ nanoparticles were successfully synthesized by two methods, namely the sonochemical method and hydrothermal method. The X-ray diffraction (XRD) patterns showed the tetragonal phase of YVO4 (JCPDS 17-0341) was indexed in the diffraction peaks of all samples. The samples synthesized by the sonochemical method had a highly crystalline structure (X-ray diffraction results) and luminescence intensity (photoluminescence results) than those synthesized by the hydrothermal method. According to the results of field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), the average size of YVO4:Eu3+ nanoparticles was around 25–30 nm for the sonochemical method and 15–20 nm for the hydrothermal method. YVO4:Eu3+ nanoparticles in the case of the sonochemical method had a better crystalline structure and stronger emissivity at 618 nm. The Eu3+ ions’ average lifetime in YVO4:Eu3+ at 618 nm emission under 275 nm excitation were at 0.955 ms for the sonochemical method and 0.723 ms for the hydrothermal method. The security ink for inkjet devices contained YVO4:Eu3+ nanoparticles, the binding agent as polyethylene oxide or ethyl cellulose and other necessary solvents. The device used for security label printing was an inkjet printer with an electrohydrodynamic printing technique (EHD). In the 3D optical profilometer results, the width of the printed line was ~97–167 µm and the thickness at ~9.1–9.6 µm. The printed security label obtained a well-marked shape, with a size at 1.98 × 1.98 mm.

Simulation & modelling of dilute solutions in drop-on-demand inkjet printing: a review

This review is about the most important matters for advancing inkjet printing with a focus on piezoelectric droplet on demand (DOD) inkjet thin-film devices. The Nano material compounds can be incorporated into a polymeric matrix and deposited by piezoelectric inkjet printing. Current problems in advanced printers are discussed as embodied in liquid filament breakup along with satellite droplet formation and reduction in droplet sizes. Various model that predicts the printability of dilute, mono disperse polymer solutions in drop-on-demand “DOD” inkjet printing have been discussed. For satellite droplets, it is exhibited which liquid filament break-up treatment can be predicted via using a combination of two pi-numbers, including the Weber number. The layer was printed over other printed layers including electrodes composed of the conductive polymers and also several polymers. It has been discussed, some polymer materials are suitable for deposition and curing at low to moderate temperatures and atmospheric pressure, allowing for the use of polymers or paper as supportive substrates for the devices, and greatly facilitating the fabrication process. Furthermore, through this review, it has been discussed scaling analyses for designing and operating of inkjet heads. Because of droplet sizes from inkjet nozzles are typically on the order of nozzle dimensions, a numerical simulation is shown for explaining how to reduce droplet sizes through employing a novel input waveform impressed on the inkjet-head liquid inflow without changing the nozzle geometries. Regardless of their any less performance, inkjet printer head as a technique for the mentioned devices presents many advantages, the most notable of which are quickly fabricating and patterning, substrate flexibilities, avoidance of material wastage via applying “DoD” technologies.

Inkjet 3D printed microfluidic device for growing seed root and stalk mechanical characterization

The 3D printing of microdevices is an emerging technique that has recently been widely reported as a new tool for developing microfluidics. Here we present for the first time an inkjet 3D-printed microfluidic device with integrated force sensors for monitoring seed growth and determining axial growth forces of the germinating seed’s root and stalk. The growth of Lepidum sativum seeds was successfully observed in the developed device. Determining the growth forces was possible thanks to knowledge of the mechanical properties of the integrated microbeams (force-deflection characteristics). The maximal growth forces were 58 mN for the root (corresponding to 0.32 MPa growth pressure) and 501 mN for the stalk.

Generation of Ultra-small Droplets by an Inkjet Device and Its Application to Analytical Chemistry

Generation of Ultra-small Droplets by an Inkjet Device and Its Application to Analytical Chemistry

Dopant doubles crystal’s piezoelectricity

Piezoelectric materials generate mechanical strain under an applied electric field, and vice versa. Over the past 20 years, these materials have come into wide use in inkjet printers, guitar pickups, and devices that generate ultrasound waves for medical imaging, among other applications. Boosting the piezoelectric charge coefficient of these materials could lead to new kinds of medical imaging, improving the resolution of ultrasound and making it possible to generate the frequencies needed to image the eye and other parts of the body currently invisible to the method, says University of Wollongong materials engineer Shujun Zhang. Along with collaborators at Xi’an Jiaotong University and Pennsylvania State University, Zhang has been working for years to improve one of the best piezoelectric materials, a lead titanate crystal called PMN-PT, by engineering its structure. This material’s high piezoelectric charge coefficient arises from heterogeneity in its crystal structure. Zhang says previous research by ...