Printing Ink Formulations Research Articles

Citrus peel powder alters the rheological properties and 3D printing performance of potato starch gel

Owing to the growing interest in sustainable resource utilization, the current study explores the potential replacement of pectin with citrus peel powder (CP) in starch-based 3D food printing ink formulations. The effect of different concentrations of pectin (1 %, 2 %, 3 %) and CP (1 %, 2 %, 3 %) on the printing fidelity, microstructure, rheological and textural properties of potato starch gel were investigated. The results showed that the 3D printing performance of CP-added inks was higher than that of pectin-added inks at all tested concentrations. The storage modulus of CP-added ink was higher than that of pectin-added ink proving higher printing fidelity of CP-added inks. Additionally, hardness, gumminess, springiness and chewiness of food ink increased with an increase in the concentration of CP while decreased with an increase in concentration of pectin. Interestingly, pectin and CP-added inks displayed similar in vitro digestibility, suggesting an insignificant effect of replacing pectin with CP on in vitro glucose release. Moreover, the antioxidant activity of CP-added ink was higher than pectin-added ink demonstrating the potential applications of CP-added ink in functional ink development. Therefore, this study claims for effective replacement of pectin with CP in starch-based 3D food printing ink formulations as a promising sustainable additive.

Structure–mechanical property relationships of 3D-printed porous polydimethylsiloxane films

Abstract Complex microstructures can be produced from different base materials by combining three-dimensional (3D) printing technology and ink formulations. The surface wettability of the 3D-printed porous polydimethylsiloxane (PDMS), particularly its superhydrophobic property, strongly depends on its physical structure. However, the mechanism underlying the effect of the microporous structure on the mechanical properties is not understood, which seriously constrains the structural–functional integration design of the 3D-printed superhydrophobic porous PDMS. To solve this problem, we studied the influence of the printing parameters on the mechanical properties in the compression and tension directions using a finite element method. The results showed that the load transfer path of the 3D-printed porous PDMS was along the overlapping area of the adjacent filaments. As the filament spacing decreased or the filament diameter increased, the elastic modulus of the porous PDMS was enhanced, improving its resistance to tensile and compressive deformation. A quantitative relationship was established between the relative densities of the porous PDMS films and their relative elastic moduli. This study provides theoretical guidance for the structural–functional integration design of 3D-printed superhydrophobic porous PDMS.

Low-cost fabrication and physicochemical characterization of ZnFe2O4 nanoparticles as an efficient multifunctional inorganic pigment

The pursuit of low-cost manufacturing of newly effective pigments is a pressing economic need. Thus, in this work, low-cost ZnFe2O4 spinel nanoparticles (ZF-NPs) with an average diameter of 20 nm were successfully synthesized using a simple sol–gel method, which can be extended for large-scale fabrication of a reddish nano pigment. TGA/DTA, XRD, DRS, HRTEM, and SEM/EDX investigations were used to characterize the as-prepared product. The color of synthesized NPs was studied using CIE L*a*b* colorimetric method with color coordinates of L* = 41.7, a* = 72.2, and b* = 48.8. The newly developed pigment was examined to be superior to the traditional pigment (M6001/Fe2O3: L* = 30.4, a* = 42.16, and b* = 45.7). After that, the synthesized nano pigment was integrated into both ink and paint formulations as a multifunctional coating. The inclusion of synthesized nano pigment in metal coating printing ink formulation was done to produce a good alternative and cost-effective substitute for the commercially available pigment used in the inks industry. Also, the effect of the fabricated nanoparticles on corrosion resistance and thermal stability of epoxy-based paint formulations was evaluated using different standard tests. Therefore, the ZnFe2O4 pigment should be applied as a highly efficient inorganic nano pigment.

Advances in printing techniques for thermoelectric materials and devices

Thermoelectric materials and devices have garnered significant attention in recent years due to their potential for converting waste heat into usable electricity, opening new avenues for sustainable energy harvesting. As research in the field of thermoelectric materials and devices continues to grow, so does the need for efficient and scalable fabrication methods. Among various fabrication techniques, printing methods have emerged as promising approaches to producing thermoelectric materials and devices, offering advantages such as low cost, high throughput, and design flexibility. Here, we overview the recent advances in printing methods for the fabrication of thermoelectric materials and devices. We discuss the key principles, challenges, and opportunities associated with various printing techniques, including screen printing, inkjet printing, and 3D printing, with a focus on their applications in thermoelectric materials and devices. Furthermore, we highlight the progress made in optimizing the printing parameters, ink formulations, and post-processing methods to enhance the thermoelectric performance of printed materials and devices. Finally, we provide insights into the prospects and potential research directions in the field of printing methods for thermoelectric materials and devices. This review aims to provide a comprehensive overview of the state-of-the-art printing techniques for thermoelectric materials and devices and to serve as a reference for researchers and practitioners working in this rapidly growing field.

Cascaded encryption/decryption using digital polymer toward high-level information security

Encoding information in digital polymers has become a promising approach for data storage in recent years. High-level information security is crucial for practical application, which is still challenging in digital polymers due to the lack of efficient techniques. Herein, we proposed a cascaded encryption/decryption approach that uses Morse-coded digital polymers to encipher sequence information as well as molecular weight distribution (MWD) information. The MWD information could be deconvoluted in size exclusion chromatography (1st decryption), whereas the 2nd decryption was performed in tandem mass spectrometry. The correct information could only be accessed after two successive decryption processes, thus providing high-level information security. Furthermore, this cascaded strategy was applied to a printing ink formulation for multidimensional anti-counterfeiting applications toward high-value artwork.

Experimental overview for green printed electronics: inks, substrates, and printing techniques

The selection of materials and technologies for green printed electronics design is a fundamental and time-consuming task. This paper represents a rigorous experimental overview in which different printing technologies, ink formulations, and paper-based substrates are examined and analyzed. Three printing techniques are investigated: inkjet printing, screen printing, and direct ink writing. Regarding the inks, formulations based on carbon and silver have been chosen as conductive materials. Initially, the electrical properties of the selected inks have been characterized on a conventional substrate in printed electronics such as polyethylene terephthalate. Later, the printing conditions are optimized for various paper-based substrates, including commercial papers and substrates based on cellulose nanofibers (CNF). CNF are also used as a coating for commercial papers and their influence on the printing quality is evaluated. The substrates are also characterized in terms of morphology, wettability, and thermal stability. This study facilitates the benchmarking tasks for researchers developing new devices and contributes toward the eco-design of flexible green printed electronics.

An Insight into Recent Advancement in Plant- and Algae-Based Functional Ingredients in 3D Food Printing Ink Formulations

An Insight into Recent Advancement in Plant- and Algae-Based Functional Ingredients in 3D Food Printing Ink Formulations

Additive manufacturing solidification methodologies for ink formulation

With the burgeoning interest in 3D printing for complex and high-resolution patterned devices, ink formulation plays a vital role for its successful utilization in various application in energy, structural and medical. This review paper will aid readers in the field of 3D printing in making an informed evaluation of the current 3D printing technologies available for practical utilization. A huge challenge in 3D printing ink formulations is in its green part strength. 3D printing technology of viscoelastic materials involves multiple steps of which, the solidification step affects the structure and functionality of the product. We have examined the different ink formulations used in 3D Printing-related journal papers and their solidification mechanisms have been organized and summarized into this review paper. One of the most commonly used solidification mechanisms is solvent-assisted drying. Although it often results in brittle green parts, solvent-based inks are versatile, economical and relatively environmentally friendly. To improve the structural integrity of viscoelastic inks, in-situ curing methods (ultra-violet light assisted, thermal assisted etc.) are utilized to increase the yield strength of the 3D printed structures. The progress, advantages, and disadvantages in three main solidification methods (namely solvent-assisted drying, ultraviolet light-assisted curing and thermal-assisted curing) for 3D printing (in particular, Direct Ink Writing (DIW)) will be discussed. A proposed outlook is also given to shade a light on the importance in selecting proper methods and made a guideline for matching the materials and applications library.

Evaluation of plant‐based oils for production of offset printing ink

AbstractThe oils and solvents are the main components of the printing ink, and the chemical composition of the ink could be harmful or toxic to human health and the environment. Therefore, there is an increasing demand to develop inks containing green, biobased, sustainable, and renewable raw materials instead of petrochemical substances. In this study, flaxseed oil (FO), pomegranate seed oil, plum kernel oil (PKO), and grape seed oil (GSO) were selected to produce offset printing inks. Pinus pinaster (P. pinaster) resin was also used in the formulation of inks to examine the effects of natural resin on ink together with vegetable oils. The phenolic content was analyzed for the resin and oils to figure out their potential antioxidant and bioactive characteristics. Optical and rheological tests were applied to evaluate the printability of the inks. L*a*b*, ΔE, density, and gloss tests were performed for optical evaluation. The viscosity, tack, and rub resistance tests were applied to perform rheological analysis. The biobased, environmental friendly, and self‐drying (cold set) offset printing inks were obtained using natural pine resin and three different plant‐based oils FO, PKO, and GSO. The printability analysis of the inks figured out the potential usage of plant‐based oils in the offset printing ink formulation.

Synthesis of eco-friendly cobalt doped willemite blue pigment from white sand for multi-applications in coatings and inks

PurposeThis study aims to investigate the possibility of synthesizing cobalt doped willemite ceramic blue pigment by using Egyptian white sand as environmental and economical raw material for multi-applications in coatings and inks.Design/methodology/approachAfter the synthesis process, the prepared blue pigment was characterized via X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis technique. Then the blue pigment was integrated into both coating and ink formulations. The effect of the prepared multifunctional coatings on corrosion resistance and thermal stability was evaluated using different standard tests. Also, the effect of inclusion of blue pigment in flexographic printing ink formulation was done.FindingsThe results showed that the coating containing the cobalt doped willemite blue pigment offered good anticorrosive performance and high thermal stability. Additionally, the presented results revealed that integration of the blue pigment in flexographic printing ink formulation enhanced fineness, gloss, viscosity and color more than the commercial one “FX 430–201.”Originality/valueIn conclusion, relied on the eco-friendly principle which can be regarded as an economic and green strategy, it can be obtained that this new pigment can provide good multifunctions such as corrosion resistance and thermal stability in coatings and good fineness, gloss, viscosity and color in inks which can enable them to be widely applied in different industries.

Solvent evaporation induced fabrication of porous polycaprolactone scaffold via low-temperature 3D printing for regeneration medicine researches

Liquid deposition modeling (LDM) is an evolving three-dimensional (3D) printing approach that mainly utilizes polymer solutions to enable the fabrication of biomedical scaffolds under mild conditions. A deep understanding of the rheological properties of polymer printing inks and the features of yielded scaffolds are critical for a successful LDM based fabrication of biomedical scaffolds. In this work, polymer printing inks comprised of Poly(epsilon-caprolactone) (PCL), sodium chloride (NaCl), and trichloromethane (CHCl3) were prepared. The rheological properties, including extrudability (shear stress, viscosity, and shear-thinning) and self-supporting ability (viscosity) of all printing inks were analyzed. Then printing performance was evaluated by measuring the die-swell ratio, 2D, and 3D printing fidelities. Finally, a series of porous PCL scaffolds were fabricated using printing inks comprised of different feed ratios (20:80, 40:60, 50:50, 60:40, and 80:20) of NaCl to PCL, and the porosity, mechanical properties, degradation behaviors, and biocompatibility were discussed. The results suggested that the printing ink formulation is greatly affected the printing performances. The increasing NaCl content in printing inks reduced shear force for extrusion, enhanced the shear-thinning behavior, increased the curing time. The dropping temperature and solvent evaporation both enhanced the self-supporting ability of the printing inks and solvent evaporation is a critical factor for the curing of the printing inks. The further evaluation demonstrated that the obtained fabricated porous PCL scaffolds were endowed with good biocompatibility and controllable porosity, mechanical features, and in vitro degradation behavior related to the NaCl content in the printing inks. This study built a fabricating method of porous polymer scaffolds by 3D printing at low temperatures for regeneration medicine researches.

Printing Conductive Nanomaterials for Flexible and Stretchable Electronics: A Review of Materials, Processes, and Applications

AbstractPrinted electronics is attracting a great deal of attention in both research and commercialization as it enables fabrication of large‐scale, low‐cost electronic devices on a variety of substrates. Printed electronics plays a critical role in facilitating widespread flexible electronics and more recently stretchable electronics. Conductive nanomaterials, such as metal nanoparticles and nanowires, carbon nanotubes, and graphene, are promising building blocks for printed electronics. Nanomaterial‐based printing technologies, formulation of printable inks, post‐printing treatment, and integration of functional devices have progressed substantially in the recent years. This review summarizes basic principles and recent development of common printing technologies, formulations of printable inks based on conductive nanomaterials, deposition of conductive inks via different printing techniques, and performance enhancement by using various sintering methods. While this review places emphasis on conductive nanomaterials, the printing techniques and ink formulations can be applied to other materials such as semiconducting and insulating nanomaterials. Moreover, some applications of printed flexible and stretchable electronic devices are reviewed to illustrate their potential. Finally, the future challenges and prospects for printing conductive nanomaterials are discussed.

Black and blue printing ink analysis by XRF, DRIFTS and Raman spectroscopy of recently discovered Gutenbergian Ars minor fragments

ABSTRACTIn 2017 Princeton University Library’s Department of Rare Books and Special Collections acquired a 1483 Venetian edition of the Opera of Horace, preserved in a late fifteenth century German binding. The binding contained previously undetected vellum binding waste fragments derived from an early Gutenbergian edition of the Ars minor of Aelius Donatus. Extensive portions of the printed fragments were attached to each of the wooden boards and remained hidden beneath the book’s paper pastedowns. In the paper conservation laboratory of the Department of Rare Books and Special Collections, the pastedowns were subsequently safely lifted from the boards via Gore-Tex damp packs to confirm the presence of unique remnants from an otherwise lost mid-fifteenth century Mainz edition of the Ars minor, a Latin grammar manual. The Ars minor was printed with the same typeface used around 1455 to print the Gutenberg Bible. The fragments featured black oil-based printing ink and a large Gothic two-line initial letter A printed in blue ink. The design of the typeface of the initial letter A mirrored the work of Johann Fust and Peter Schoeffer, one-time partners of Gutenberg. The pair produced the Mainz Psalter (1457), the first book printed in more than one color.The printing inks of the Ars minor were subsequently analyzed in the paper conservation laboratory in situ noninvasively by X-ray fluorescence spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy and fiber optic Raman spectroscopy. The analysis found amounts of copper and lead, in addition to amber resin and linseed oil, in the black oil-based printing ink. The copper-lead aspect of the Ars minor’s black printing ink formulation appeared to be the same basic recipe composition conceived by Johannes Gutenberg for printing with movable metal type. Indigo (indigotin) and lead white (basic lead carbonate) were identified as the components in the blue printing ink of the two-line initial letter A, and vermilion (mercury sulfide) in manually rubricated red ink. The Ars minor represents a very important find of a previously unknown early Gutenbergian work.

Effect of different surfactant monomers on alkali soluble emulsion polymer as a binder for water based printing inks

In this study hydrophobically alkali-soluble emulsion HASE was prepared by using semi batch emulsion polymerization technique and evaluated as a binder for water based printing inks. HASEwas prepared by using vinyl acetate and methyl methacrylate as hydrophobic monomers in addition to meth acrylic acid as a hydrophilic monomer. Besides, anionic and nonionic emulsifiers are used and sodium per sulfate as initiator. Three types of surfactant monomers are prepared by esterification of an acid or an anhydride with nonionic surfactant and then, the chemical structures were characterized using FT-IR spectroscopy. Each surfactant monomer was used in different ratios to prepare the emulsion polymer. However a sample without using of surfactant monomer was prepared for comparison. The prepared HASE was diluted and then neutralized by using mono ethanol amine till pH from 8 to 9. Neutralized polymer solution was mixed with pigment dispersion and then applied on paper sheet and color strength was measured. The best final polymer latex was characterized by FT-IR, DSC, and TEM. The prepared polymer showed advanced behavior compared with commercial binder in water based printing ink formulations. The results obtained revealed that uses of 5g of surfomer in polymerization of HASE enhance the color strength and gravimetric conversion and reduce the precipitate and viscosity.

Porous bioceramics produced by inkjet 3D printing: Effect of printing ink formulation on the ceramic macro and micro porous architectures control

Hierarchical structures with tailored macro/micro-porosity architecture play an important role in bone tissue regeneration. In 3D printing process, the printing ink formulation will influence on the ceramic macro and micro porous architectures. In this paper, HA powders of nano-sized grains (NP) with diameters of 30–50 nm, air jet milling powders (AP) with diameters of 10–30 μm, and spherical powder (SP) with diameters of 10–50 μm, were used as the initial printing materials in the printing ink formulations. The viscosity and the rheological behavior of printing inks were studied. The microstructure and morphology of the printed scaffold were observed and the mechanical properties of different types of scaffolds were tested. The results showed that the initial printing materials would influence on printing performance, both of the AP and SP inks may print porous scaffolds successfully. However, NP printing inks exhibited dramatic shrinkage and it is not suitable for 3D printing of bioceramics. The printing ink formulation also have effects on the ceramic macro and micro porous architectures and mechanical properties. The maximum compressive strength of SPS were 5.5 MPa, 3.2 MPa and 0.9 MPa with porosities of 60%, 70% and 80%, respectively. As the macroporosity decreases, the mechanical properties of the material would drop dramatically. With the same porosities, the compressive strength of APS were slightly higher than that of the SPS specimens.

Single Additive Enables 3D Printing of Highly Loaded Iron Oxide Suspensions.

A single additive, a grafted copolymer, is designed to ensure the stability of suspensions of highly loaded iron oxide nanoparticles (IOPs) and to facilitate three-dimensional (3D) printing of these suspensions in the filament form. This poly (ethylene glycol)-grafted copolymer of N-[3(dimethylamino)propyl]methacrylamide and acrylic acid harnesses both electrostatic and steric repulsion to realize an optimum formulation for 3D printing. When used at 1.15 wt % (by the weight of IOPs), the suspension attains ∼81 wt % solid loading-96% of the theoretical limit as calculated by the Krieger-Dougherty equation. Rectangular, thick-walled toroidal, and thin-walled toroidal magnetic cores and a porous lattice structure are fabricated to demonstrate the utilization of this suspension as an ink for 3D printing. The electrical and magnetic properties of the magnetic cores are characterized through impedance spectroscopy (IS) and vibrating sample magnetometry (VSM), respectively. The IS indicates the possibility of utilizing wire-wound 3D printed cores as the inductive coils. The VSM verifies that the magnetic properties of IOPs before and after the ink formulation are kept almost unchanged because of the low dosage of the additive. This particle-targeted approach for the formulation of 3D printing inks allows embodiment of a fully aqueous system with utmost target material content.

Analysis and optimization of water-based printing ink formulations for polyethylene films

Water-based ink formulations containing wax, surfactant, and defoamer additives were prepared and printed on polyethylene film substrates. Standard test methods for adhesion, rub resistance, and gloss were done on the printed polyethylene films. Quantitative methods for the assessment and evaluation of the three print properties were developed. Image analyses were done to quantify adhesion and rub resistance. Quantitative measurement was done to quantify gloss. Data were analyzed using mixture design modelling and optimization. Modelling results show that adhesion and gloss are described by special cubic model equations, while rub resistance is described by a linear model equation. Contour plots and 3D surface graphs were generated showing the response surfaces of the print properties. The effects of varying the mass fractions of wax, surfactant, and defoamer on adhesion, rub resistance, and gloss were determined. It was found that increasing wax increases rub resistance, while increasing surfactant increases gloss, and increasing defoamer increases adhesion. There is dependency found between the mass fraction of wax, surfactant and defoamer with respect to the rub resistance, adhesion and gloss. Multi-objective optimization revealed that optimum adhesion, rub resistance, and gloss is obtained by a formulation containing equal mass fractions of wax and surfactant but no defoamer.

The formulation and characterization of 3D printed grafts as vascular access for potential use in hemodialysis.

Arteriovenous graft (AVG) failure continues to be a life-threatening problem in haemodialysis. Graft failure can occur if the implanted graft is not well-matched to the vasculature of the patient. Likewise, stenosis often develops at the vein-graft anastomosis, contributing to thrombosis and early graft failure. To address this clinical need, a novel ink formulation comprised of ACMO/TMPTA/TMETA for 3D printing a AVG was developed (ACMO-AVG), in which the printed AVG was biocompatible and did not induce cytotoxicity. The ease of customizing the ACMO-AVG according to different requirements was demonstrated. Furthermore, the AVG displayed similar mechanical properties to the commercially available arteriovenous ePTFE graft (ePTFE-AVG). Unlike ePTFE-AVG, the ACMO-AVG displayed excellent anti-fouling characteristics because no plasma protein adsorption and platelet adhesion were detected on the luminal surfaces after 2 h of incubation. Similarly, exposure to human endothelial cells and human vascular smooth muscle cells did not result in any cell detection on the surfaces of the ACMO-AVG. Thus, the present study demonstrates a newly developed 3D printing ink formulation that can be successfully 3D printed into a clinically applicable vascular access used for haemodialysis.

Effects of the Amount and Type of Diol Ring Openers on the Properties of Oligolactide Acrylates for UV-Curable Printing Inks

This study aimed to synthesize low viscosity oligolactide acrylates for UV-curable inks from oligolactide diols. Firstly, low molecular weight oligolactide diols were prepared by ring opening reaction of L-lactide with diols. Oligolactide acrylates were then synthesized by functionalizing the oligolactide diols with acrylic acid. In this study, three diol ring openers having short and long alkyl chain length were used to investigate the effects of the amount and type of diols on the properties of the oligolactide acrylates. The obtained oligomers were characterized, and the viscosities of oligolactide acrylates were measured. Results showed that oligolactide acrylates were successfully synthesized in all cases of ring openers, as confirmed by 1H-NMR (proton nuclear magnetic resonance spectroscopy) and FTIR (Fourier transform infrared spectroscopy). An increase in the alkyl chain length of the ring openers resulted in oligomers with lower viscosity and a decrease in Tg. Following that, the obtained oligolactide acrylates were employed for the formulation of UV-curable screen printing inks and their properties were investigated. Results showed that the inks formulated from oligomers with lower molecular weight exhibited better ink flow. Additionally, all ink films cured by UV radiation were very flexible with excellent adhesion, high impact resistance, and excellent water resistance.

Digital printing of acrylic fabric with cationic dyes using conventional inkjet printer

AbstractA special printing ink formulation based on cationic dyes is developed for digital printing of acrylic fabrics using a conventional inkjet printer. In order to investigate the contribution of color gamut boundary of printer colorants to printing efficiency, customized color targets containing 3164 color patches in 25 different hues were generated. The printed color patches were then fixed through steaming for 30 minutes followed by washing with hot soap and water and finally drying. To show the influence of dye fixation on colorimetric changes as well as color gamut boundary of samples, the L*a*b* values of color patches before and after fixation process were compared. Results demonstrate that color saturation of samples is enhanced dramatically after the dye fixation process. In fact, 3D color gamut of color patches has been drastically expanded as a direct consequence of adsorption to absorption transition. Additionally, dye fixation changes the structure of printed image from halftone superimposed dots to contone superimposed dyes. Strictly speaking, during fixation process, colors inside the halftone dots diffuse through the interfacial area to make the individual printed dots integrated. This is in analogy to the chromogenic photography films and dye‐sublimation thermal transfer processes by which contone images are produced. Moreover, dye fixation improves the washing fastness of digitally printed acrylic fabrics to the level comparable with the traditional screen printing method. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 244–249, 2017