Gold Ink Research Articles

The Black Hours: Material and Conservation Study, Part 1

ABSTRACT The Book of Hours of Galeazzo Maria Sforza, V. Duke of Milan (Vienna, Austrian National Library, Codex 1856), the so-called Black Hours, is a Flemish illuminated manuscript with silver and gold ink on black coloured parchment from the third quarter of the fifteenth century. The severe deterioration of the parchment by the black colourant resulted in brittleness and numerous losses. This paper describes the history of the manuscript and previous interventions. The condition of the various materials was assessed and put in context with the other six black manuscripts that have been preserved worldwide. The fibre morphology, the hydrothermal stability and the investigation of the fibre structure in the Scanning electron microscope confirmed the degradation of the parchment fibres. The black colourant was identified as iron gall ink by X-ray fluorescence spectrometry (XRF) and Raman spectroscopy. The elemental composition of silver and gold was analysed with XRF. Based on these results, a model conservation treatment and a new preservation solution were developed.

Writing in Gold and Silver. Byzantine Ink Recipes from MS Bononiensis 1808

The article examines six hitherto unpublished Byzantine recipes for the production of gold and silver inks preserved in MS 1808 of the University Library of Bologna. The study of these recipes raises a number of problems of interpretation regarding the substances and procedures involved, which we seek to resolve by taking into account the philological and linguistic aspects as well as the chemical and technological ones.

Development of Gold Inks for Inkjet Printing of Gas Sensors Electrodes on Plastic Support

Among the conventional inks used for inkjet printing, metals, oxides, or polymers have been deposited in order to form functional coatings. Gold is one of the most used metals for electrode fabrication in the gas sensor field due to its inert behavior when exposed to reactive gases and conductive properties. However, only a few commercial gold inks are commercially available, and the combination of excessive price, a high minimum purchase quantity, and an unknown composition renders the actual products unappealing. To meet these shortcomings, gold inks were formulated with different solvents in order to reach sufficient properties for the inkjet printing process, such as surface tension and viscosity. On the one hand, gold ink was developed using a gold nanoparticle (AuNP) solution as the metal. This ink was optimized from nanoparticle synthesis, with the ink formulation obtaining a 32 mN·m−1 surface tension and 11.2 mPa·s viscosity in order to be inkjet-printed onto polyimide foil. On the other hand, a particle-free ink, called a precursor based of ink, was also developed. In this case, ink was made by solubilizing gold salt in aqueous medium in order to reach jettable properties. Surface tension was measured at 32 mN·m−1 while viscosity was 14.0 mPa·s. Then, printing and deposition parameters were optimized in order to obtain a highly conductive gold coating. The measured resistivity was 2 × 10−7 Ω·m which is close to the bulk gold conductive value. These coatings could be used for the fabrication of various devices in different working fields.

The Dagulf Psalter (Austrian National Library Cod. 1861): A Multi-Analytical Approach to Study Inks, Dyes, and Pigments of this Early Carolingian Manuscript

Abstract The Dagulf Psalter is a precious Carolingian manuscript on calf parchment, dated to 793–795. Its unique and high historical value required a non-invasive, multi-analytical approach to gain insights into the material composition of gold and silver inks, pigments, and dyes used for writing and illuminations. Elemental mapping based on X-ray fluorescence analysis (XRF), Fibre Optics Reflectance Spectroscopy (FORS) measurements, and hyperspectral imaging (HSI) gave complementary information on colour media and their brilliant shades. Knowledge of the material composition of inks, dyes, and pigments is of crucial importance not only for art historical research, but also for the preservation of the manuscript, as it is known that among other factors, silver inks and some pigments can lead to deterioration of parchment supports. The purple dye orchil and blue indigo were used for painted backgrounds on the initial folios. Lapis lazuli was found in decorative frames on these folios. Orchil, indigo, and lapis lazuli also appear in decorations of small initials throughout the manuscript. Red lead, ochre, cinnabar, orpiment, and lead white were also found in various painted details. Gold and silver inks of high purity were identified. The proof of chlorine in the silver ink indicates the presence of corrosion products.

High-Temperature Melt Stamping of Polymers Using Polymer/Nanoporous Gold Composite Stamps.

Parallel lithographic deposition of polymers onto counterpart substrates is a widely applied surface manufacturing operation. However, polymers may only be soluble in organic solvents or are insoluble at all. Solvent evaporation during stamping may trigger hardly controllable capillarity-driven flow processes or phase separation, and polymer solutions may spread on the counterpart substrates. Solvent-free stamping of melts prevents these drawbacks. Here, a stamp design for the deposition of melts is devised, which intrinsically circumvents ink depletion. The stamps' topographically patterned contact surfaces with protruding contact elements contacting the counterpart substrates consist of a nanoporous gold layer with a thickness of a few micrometers. The nanoporous gold layer is attached to a molten polymer layer, which is support for the nanoporous gold layer and ink reservoir at the same time. The nanoporous gold layer in turn stabilizes the topography of the stamps' contact surfaces. As examples, arrays of submicron microdots of polystyrene and poly(vinylidenefluoride-trifluoroethylene) (PVDF-TrFE) are manufactured. The P(VDF-TrFE) microdots are partially crystalline, ferroelectric, and can be locally poled. It is envisioned that the methodology reported here can be automatized and may be extended to functional low-molecular-mass compounds, such as active pharmaceutical ingredients.

Islamic Intellectual Movement Patterns

The occurrence of cultural contact between the West and East awakens Muslims, depending on the problems that arise and are faced by the intellects in a country, so that the forms of scientific movement patterns that can not be respected from social, economic, and social backgrounds. politics and religion that surrounds it. Its role globally is recorded neatly in gold ink in many pages of history. Under Islamic control, his views on ideological independence and his attitude towards the rules of life were very clear, which was marked by syumuliah (universality) because he was indeed handed down as a living system. The long journey of intellectuals and works that have been carved by Indonesian scholars is an invaluable source of information in exploring their thinking models when facing the development of the situation and the demands of their times. It seems interesting to examine the implications of their thinking on the dynamics of contemporary Islamic thought and modernization. Most of them have created educational models that are unique and interesting and remain relevant at all times. How do the scholars who have specialized themselves to study and teach their knowledge, have a high enthusiasm to continue the legacy of the Prophets to all Muslims without knowing the territorial boundaries. The love of knowledge, the struggle to gain knowledge, and their preservation of knowledge are exemplary for Muslims today. On knowledge is also able to deliver to become a great figure throughout the ages who leave traces (atsar) that are good for the next generation. This paper seeks to explore the patterns used by Muslim intellectuals in the history of Islam of the various movements used in facing challenges.

Winter Drawings on the Université de Montréal Campus

These sketches, drawn from my work-place, show the area around the Université de Montréal environmental design faculty in winter. From the windows where I drew them (sheltering from the cold), we see the surrounding landscape, as well as the mountain in the distance, through the leafless trees. These drawings, in black and gold ink and watercolor, evoke, on a small scale, the connections between the city and the landscape of the mountain – Mount Royal, the emblem of Montréal. Like landscape paintings with multiple grounds, they speak of the public space, the winter vegetation with its mesh of branches and the icons of Montréal.

(Digital Presentation) Printed Wearable Electrochemical Sensor for Monitoring Human Performance Markers during Human Spaceflight

Additive manufacturing technologies are being explored by NASA for the in-space manufacturing of sensors and electronics. Additive manufacturing directly addresses the logistic challenge for long-duration human spaceflight missions while also offering a high degree of customization and tailorability. To ensure the health and safety of crew members during long duration missions, it can be advantageous to develop human health diagnostic tools that can be manufactured during those missions. Here we report the development of a wearable and fully printed electrochemical sensor for the detection of human performance markers in sweat.1 The sensor’s fabrication is complimentary with in-space manufacturing for an on-demand and hands-free fabrication and is comprised of commercial and custom carbon, gold and silver inks on a polyimide substrate to make a flexible, 3-electrode electrochemical sensor, shown in Figure 1. Sensor readout is performed using standard electrochemical procedures via a miniaturized, custom potentiostat. The initial prototyped printed electrochemical sensors demonstrate good electrochemical performance and high mechanical stability while also displaying low batch to batch variability. Our goal is to create a highly adaptable and versatile approach that utilizes fabrication processes consistent with in-space manufacturing, thus enabling the manufacture of point-of-care devices during flight.Reference Brasier, N. & Eckstein, J. Sweat as a Source of Next-Generation Digital Biomarkers. Digit. Biomarkers 3, 155–165 (2019). Figure 1

Reliable Paper Surface Treatments for the Development of Inkjet‐Printed Electrochemical Sensors

AbstractThe need for disposable, simpler, and accurate paper‐based analytical devices represents an open research field that is focused on simpler fabrication methods. To achieve this, four feasible methodologies are proposed for the direct printing of an electrochemical sensor on a biodegradable paper substrate using commercial gold and silver inks, which are compatible with inkjet printing technology. Four substrate treatment strategies are evaluated: printing the active elements directly on the hydrophilic bare paper, a hydrophobic gas‐phase coating over all the substrate, a hydrophobic silane ink that is selectively printed on the paper, and a hydrophobic coating that is selectively printed and blocks the surface porosity. Thanks to the ability of the inks to conform the cellulose fibers, the resulting working electrodes tune their electrochemical active area, showing higher active electrochemical areas when the roughness is increased. The most planar consideration is achieved blocking the paper porosity with SU‐8 and the direct printing on bare paper maximizes the electrochemical response with the smallest geometric area, with current values 2.7‐times higher than the theoretical one. Although all methods allow a functional electrochemical sensor, the highest reproducible results are accomplished with the blocked paper, consequently allowing a higher controlled and robust manufacturing approach.

The role of reverse micelles and metal-surfactant interactions in the synthesis of gold ink in reverse emulsions stabilized by AOT, Tergitol NP-4 and Span 80

The development of advanced methods for the synthesis of metal-containing solvent ink is important for 2 and 3D printing as well as for obtaining composites of nanoparticles with hydrophobic polymers. The formation mechanism of gold organosols in reverse emulsions stabilized by the widely used surfactants AOT, Tergitol NP-4 or Span 80 was investigated. It was found that the main factors promoting the successful synthesis are the presence of small size reverse micelles in a dispersion medium and the occurrence of interaction of a surfactant with the complex anion AuCl4–. The interaction provides a rapid transfer of gold ions from the micron size emulsion droplets to nanometer micelles. After that, the micelles play their conventional role of nanoreactors, limiting the growth and stabilizing a nanoparticle during the reduction of AuCl4– by hydrazine. After destruction of the emulsion and separation of the aqueous phase, the sols were subjected to additional electrophoretic concentration. It was demonstrated that the obtained concentrate can be used as the solvent ink to form conductive films and composites of nanoparticles with hydrophobic polymers like polystyrene, where nanoparticles retain the properties of plasmonics. The novelty and significance of the study in terms of colloidal and surface chemistry consist in the fundamental and experimental substantiation of the new and promising application of such a classical colloid as reverse emulsions.

Printed electronics for extreme high temperature environments

There is a rapidly growing interest in the development of electronic microsystems that can maintain functionality in high temperature environments, particularly in power generation and aircraft engines where the operating temperatures can exceed 500 °C. The current work presents a major advancement toward development of additively printed electronics made for high temperature applications. Here, the electronic system is represented by gold-based electrical structures that have been printed on 3D printed ceramic substrates. The substrate is alumina-based with a purity level of 99.8% and was fabricated through photopolymerization digital light processing (DLP). An aerosol jet printing technique that can deposit an ink stream down to 10 µm was utilized to fabricate gold-based electronic structures. The gold ink printability and its adhesion to the ceramic substrate were assessed. Furthermore, the microwave dielectric constant and loss tangent of the alumina substrate were extracted through measurements of the scattering parameters of transmission lines up to 750 °C. A 3D printed conformal broadband antenna was successfully fabricated and tested at temperatures up to 850 °C. The printed gold structures showed excellent stability and adhesion after aging at temperatures up to 750 °C. The substrate dielectric constant slightly increased for temperatures up to 450 °C and significantly increased for temperatures between 450 °C and 750 °C. It was found that the dielectric loss increased as the temperature increased. This work presents an entirely additive manufacturing-based approach to fabricate electronic components including substrates, interconnects, and RF elements for high temperature applications.

Inkjet-Printed Three-Electrode System on Flexible Substrate for Low-Cost Electrochemical Analysis

Inkjet printing (IJP) has emerged as a promising additive manufacturing technique for fabrication of electrodes and sensors due to its cost-effectiveness compared to the traditional techniques, such as screen-printing. In this work, we present a planar, three-electrode system fabricated by inkjet printing on a polyethylene naphthalate (PEN) flexible substrate for rapid voltametric electrochemical analysis. An in-house formulation of aqueous-based gold ink with low temperature-sintering was used in printing the working and counter electrodes. The reference electrode was also inkjet-printed using a commercial silver ink and chlorinated to form an AgCl layer. Cyclic voltammetry studies using the ferri/ferrocyanide redox couple showed that the inkjet-printed electrode system has a comparable electrochemical performance to a commercial screen-printed electrode. Fabrication of a single inkjet-printed electrochemical 3-electrode platform consumes only about 0.5 mg Au and 0.2 mg Ag loading of ink with minimal waste during fabrication because of the additive nature of the printing technique. The 3-electrode platform operates with a microliter sample volume for analysis and can be used in aqueous media without delamination.

Embedding of Ultrathin Chips in Highly Flexible, Photosensitive Solder Mask Resist.

This work presents an embedding process for ultrathin silicon chips in mechanically flexible solder mask resist and their electrical contacting by inkjet printing. Photosensitive solder mask resist is applied by conformal spray coating onto epoxy bonded ultrathin chips with a daisy chain layout. The contact pads are opened by photolithography using UV direct light exposure. Circular and rectangular openings of 90 µm and 130 µm diameter, respectively, edge length are realized. Commercial inks containing nanoparticular silver and gold are inkjet printed to form conductive tracks between daisy chain structures. Different numbers of ink layers are applied. The track resistances are characterized by needle probing. Silver ink shows low resistances only for multiple layers and 90 µm openings, while gold ink exhibits low resistances in the single-digit Ω-range for minimum two printed layers.

Specially Designed Polyaniline/Polypyrrole Ink for a Fully Printed Highly Sensitive pH Microsensor.

pH sensing for healthcare applications requires sensors with mechanically stable materials of high sensitivity and high reproducibility combined with low-cost fabrication technologies. This work proposes a fully printed pH sensor based on a specially formulated conducting polymer deposited on a microelectrode in a flexible substrate. A formulation, which combined polyaniline (PANI) and polypyrrole (PPy) with integrated polyelectrolyte poly(sodium 4-styrenesulfonate) (PSS), was specially prepared to be printed by inkjet printing (IJP). The sensor has good sensitivity in the physiological region (pH 7–7.5) key for the healthcare biosensor. This mixture printed over a commercial gold ink, which has a singular chemical functionalization with phthalocyanine (Pc), increased the sensor sensitivity, showing an excellent reproducibility with a linear super-Nernstian response (81.2 ± 0.5 mV/pH unit) in a wide pH range (pH 3–10). This new ink together with the IJP low-cost technique opens new opportunities for pH sensing in the healthcare field with a single device, which is disposable, highly sensitive, and stable in the whole pH range.

Gold Inks for Inkjet Printing on Photo Paper: Complementary Characterisation.

Nowadays, cost-effective, available, and flexible paper-based electronics play an essential role in the electronics industry. Herein, we present gold nanoparticles (AuNPs) as a potential raw material for gold inks in the future for such purposes. AuNPs in this research were synthesised using the ultrasonic spray pyrolysis (USP) technique from two precursors: gold (III) chloride tetrahydrate and gold (III) acetate. Synthesised AuNPs were collected in a suspension composed of deionised (D.I.) water and the stabiliser polyvinylpyrrolidone (PVP). AuNPs’ suspensions were subjected to the rotavapor process to obtain gold inks with higher Au concentration (>300 ppm). ICP-MS measurements, the size and shape of AuNPs, ζ-potential, Ultraviolet-visible (UV-Vis) spectrophotometry measurements, and scanning electron microscop y (SEM) of gold inks were carried out in order to find the optimal printing parameters. In the final stage, the optical contact angle measurements were performed using a set of polar to non-polar liquids, allowing for the determination of the surface free energy of gold inks. Inkjet printing of gold inks as defined stripes on photo paper were tested, based on the characterisation results.

Testing of novel nano gold ink for inkjet printing

Testing of novel nano gold ink for inkjet printing

Inkjet-Printing of Nanoparticle Gold and Silver Ink on Cyclic Olefin Copolymer for DNA-Sensing Applications.

Inkjet technology as a maskless, direct-writing technology offers the potential for structured deposition of functional materials for the realization of electrodes for, e.g., sensing applications. In this work, electrodes were realized by inkjet-printing of commercial nanoparticle gold ink on planar substrates and, for the first time, onto the 2.5D surfaces of a 0.5 mm-deep microfluidic chamber produced in cyclic olefin copolymer (COC). The challenges of a poor wetting behavior and a low process temperature of the COC used were solved by a pretreatment with oxygen plasma and the combination of thermal (130 °C for 1 h) and photonic (955 mJ/cm²) steps for sintering. By performing the photonic curing, the resistance could be reduced by about 50% to 22.7 µΩ cm. The printed gold structures were mechanically stable (optimal cross-cut value) and porous (roughness factors between 8.6 and 24.4 for 3 and 9 inkjet-printed layers, respectively). Thiolated DNA probes were immobilized throughout the porous structure without the necessity of a surface activation step. Hybridization of labeled DNA probes resulted in specific signals comparable to signals on commercial screen-printed electrodes and could be reproduced after regeneration. The process described may facilitate the integration of electrodes in 2.5D lab-on-a-chip systems.

Laser Irradiation for Improving the Wetting of Nanoparticle Gold Inks for Printed Electronics

Digital printing technologies, such as inkjet or aerosol jet, are becoming increasingly interesting for the manufacturing of electronic devices. As a maskless and contactless process, it offers the potential for low-cost deposition of functional materials onto flat, flexible, or 3-D substrates. Common inks used for printed electronics are nanoparticle (NP) metal inks. Silver (Ag) is widely used because of its excellent conductivity, but also gold (Au) inks are of interest for several applications. By using NP inks, it is possible to integrate conductive paths and sensors onto temperature-sensitive substrate materials, such as polymers. Polymers often need a pretreatment, such as a plasma treatment for improving the wetting. Plasma treatment usually changes the wetting behavior of the complete substrate surface. This could be critical for some applications, e.g., fluidic applications, where the original properties of the substrate should be kept. Low-pressure plasma as a vacuum process is also difficult for implementation into an existing process. In this article, laser irradiation for local improvement in wetting of an inkjet-printed gold ink on polymer substrates is investigated. The experiments show that laser irradiation is a very promising technique for the modification of polymer surfaces and suitable for inkjet printing NP inks on hydrophobic polymer surfaces. This offers new opportunities for printed electronics, which could be easily integrated into the existing processes.

Inkjet printing of metal nanoparticles for green UHF RFID tags

Abstract. UHF RFID tags are nowadays widely and successfully implemented in many distinct applications, but unfortunately the traditional production process and incorrect disposal of such devices have a negative impact on the environment. In this work silver and gold nanoparticle inks were printed by a consumer inkjet printer on eco-friendly substrates like paper and PET in order to make the manufacturing process less harmful to the ecosystem. A dipole antenna with matching loop was designed for the RFID chip EM4325 from EM Microelectronics, which has an integrated temperature sensor, at the frequency of 866 MHz. Based on this design, simulations of the greener tags are presented and compared as a proof of concept, without optimizing the designs at first for the different materials. The printings with silver (unlike the gold) were conductive with self-sintering. IPL sintering was conducted to reduce the sheet resistance from the silver ink and to turn the gold ink conductive. First S11 parameter and read distance measurements are shown as well as the simulations with the optimized antenna designs.

Application of metallic inks based on nickel-silver core–shell nanoparticles for fabrication of conductive films

Conductive inks based on nickel nanoparticles (NPs) have attracted much attention as a low-cost replacement for the currently used silver and gold inks, for fabrication of printed electronic circuits and devices. Nickel NPs as a component of conductive inks should be stable against oxidation process at all stages of preparation of conductive patterns: ink formulation and storage, printing, and post-printing treatment. In the present study, the oxidation resistance of the Ag layer and the conductive properties of the Ni core allowed the use of nickel-silver core–shell (Ni@Ag) NPs as the component of conductive ink. Thick films composed of Ni-Ag core–shell NPs were deposited on a glass substrate and then sintered at temperatures ranging from 250 °C–370 °C. The conductivity of Ni@Ag coatings after sintering at 350 °C reached 11% of that for a bulk nickel.