Tuschenanalyse im P 11702

Near-infrared reflectography and imaging X-ray fluorescence analysis reveal that carbon inks of two different compositions were used in the papyrus manuscript Berlin P 11702. In contrast with the writing ink, one of the carbon drawing inks contained a significant addition of iron. This result emphasizes the need for routine instrumental ink analysis.

Nanocellulose based carbon ink and its application in electrochromic displays and supercapacitors.

Conventional electronics have been highlighted as an unsustainable technology; hazardous wastes are produced both during their manufacturing but also, due to their limited recyclability, during electronic end of life cycle (e.g., disposal in landfill). In recent years additive manufacturing processes have attracted significant interest as a more sustainable approach to electronic manufacturing. Despite the field of printed electronics addressing some of the issues related to the manufacturing of electronics, many components and inks are still considered hazardous to the environment and are difficult to recycle. Here we present the development of a low environmental impact carbon ink based on a non-hazardous solvent and a cellulosic matrix and its implementation in electrochromic displays and supercapacitors. As part of the reported work, a different protocol for mixing carbon and cellulose nanofibrils (CNF) (rotation mixing and high shear force mixing), nanocellulose of different grades and different carbon: nanocellulose ratio were investigated and optimized. The rheology profiles of the different inks showed good shear thinning properties, demonstrating their suitability for screen-printing technology. The printability of the developed inks was excellent and in line with those of reference commercial carbon inks. Despite the lower electrical conductivity (400 S/m for the developed carbon ink compared to 1000 S/m for the commercial inks), which may be explained by their difference in composition (carbon content, density and carbon derived nature) compared to the commercial carbon, the developed ink functioned adequately as the counter electrode in all screen-printed electrochromic displays and even allowed for improved supercapacitors compared to those utilizing commercial carbon inks. In this sense, the supercapacitors incorporating the developed carbon ink in the current collector layer had an average capacitance = 97.4 mF/cm2 compared to the commercial carbon ink average capacitance = 61.6 mF/cm2). The ink development reported herein provides a step towards more sustainable printed electronics.

Florentine papyri under examination: the material study of the inks used at the beginning of the Common Era in the “Family of Kôm Kâssûm” Archive (Hermopolis)

Carbon inks with metallic admixtures are found on some papyri of the 2nd century CE from a family archive in Hermopolis. The great diversity of inks found in a single household within a short period of time suggests that inks were purchased rather than self-made.

Looking for the missing link in the evolution of black inks

In the transition from carbon to iron-gall inks, the two documents from the Egyptian Museum and Papyrus Collection in Berlin with shelfmarks P 13500 and P 13501 discussed in this work present an important case. Their inks appear brownish, although they date back to the fourth and third century BCE, when carbon inks are believed to have been commonly if not exclusively used. Using imaging micro-X-ray fluorescence and infrared reflectography, we discovered that the inks in both documents contain a significant amount of copper in addition to carbon. Comparing the extant recipes for black writing inks and the experimental evidence, we suggest that these inks are a transition between the pure carbon and the iron-gall inks. Such inks may have been quite common before the production of iron-gall ink was clearly understood and established.

Advanced Manufacture by Screen Printing

Screen-printing is the most widely used process in printed electronics, due to its ability to transfer materials with a wide range of functional properties at high thickness and solid loading. However, the science of screen printing is still rooted in the graphics era, with limited understanding of the fundamental science behind the ink transfer process. A multifaceted approach encompassing all aspects of the production of printed electronics from ink formulation, through screen-printing and post processing was therefore undertaken. With a focus on carbon inks due to their electrical conductivity, low cost, inertness and ability to be modified or functionalised. Parametric studies found that with blade squeegees, lower angles and softer blades led to increases in ink deposition, irrespective of ink rheology. However, the effects of print speed and snap distance were related to the rheology of the inks. Existing computational models were inaccurate and based on two contrasting theories. Extensional CaBER testing provided qualitative indications of the effect of separation speed and distance on deposition. However, this could only assess the effect of vertical, 2-dimensional forces and could not evaluate the influence of shear forces due to separation angle or the effects of the screen mesh. For this purpose, a screen-printing visualisation rig was specifically constructed, allowing the ink transfer mechanism to be captured for the first time. This identified similarities with one of the two theories, although existing models had oversimplified the process and did not account for variations in lengths of the separation regions or the contact angle between the mesh and substrate. It was also found that changes in the ink rheology and parameter settings changes the lengths of these regions, as well as the shape and presence of filaments formed during separation. The parameters of print speed, snap distance, solid loading and ink rheology were assessed and found to affect the mesh/substrate contact time and filamentation behaviour. This had a quantifiable effect on ink deposition, in terms of the amount of ink transfer, roughness and therefore conductivity. Finally, photonic annealing and subsequent compression rolling were found to enhance the conductivity of carbon inks by removing binder between particles and consolidating the ink film, leading to 8 times reduction in resistivity for a graphite-based ink and halving in resistivity for an ink containing a combination of carbon black and graphite, where there was less potential for improvement due to the conductive bridges between the graphite flakes.

PRECISE COMPLEX MICRO-TEXTURING INTO STAINLESS STEELS BY PLASMA PRINTING

The plasma printing was used to make precise micro-texturing into the stainless steels to have complex textured geometry. First in this plasma printing, the original two dimensional micro-patterns were drawn onto the substrate surface by the maskless patterning with use of the nano-carbon ink. These micro-patterned specimens were further plasma-nitrided at 673 K for 5.4 ks by 70 Pa with use of the hollow cathode device. The unprinted surface areas were selectively nitrided to have high nitrogen solute contents up to 12 mass%. The masked area just corresponded to the carbon-mapping from the printed nano-carbon inks, while the unprinted surface, to the nitrogen mapping. The hardness profile had stepwise change across the borders between these printed and unprinted areas; e.g., the hardness on the unprinted surface was 1200 Hv while it remained to be 350 Hv on the printed surface. This selective nitriding accompanied with the selective hardening. This selective nitriding enabled us to construct the three dimensionally textured miniature dies and products by chemical etching of the printed area.

A Fragment of an Ancient Hymnody Manuscript from Mǝʾǝsar Gwǝḥila (Tǝgray, Ethiopia)

The article presents a multidisciplinary analysis of an old fragment of a hymnody manuscript recently recorded in one of the ecclesiastic libraries of East Tǝgray. The handwriting on the fragment demonstrates pre-14th century palaeographic features. A peculiarity of the text is represented by the so-called “odd vocalization”, with many words vocalized in a way different from the standard Gǝʿǝz. The content of the fragment is a sequence of antiphons, some having been identified. A non-destructive material analysis, aimed at identifying the chemical components of the inks, revealed that the black ink used in the fragment is dissimilar from the common carbon inks attested in more recent manuscripts of the same ecclesiastic library. It does contain a high quantity of iron and a few other metals; however, it cannot be plainly identified as iron-gall-inks.