TY - BOOK

T1 - Inkjet Printing: A Versatile Method for The Fabrication of Functional Patterns

AU - Samusjew, Aleksandra

N1 - embargoed until 01-03-2024

PY - 2019

Y1 - 2019

N2 - Inkjet printing is a technique where a digital image is being reproduced on an even surface by depositing a vast amount of picolitre sized drops on the substrate. This method allows an easy and efficient printing of text and graphics, without the necessity for the impression cylinders or printing blocks. Thereby, there is a growing interest in this technology for the manufacturing of functional patterns in areas such as electronics, optics or life sciences. This work focused on the research and development of the inks for optics and electronics, and inks for graphics that are suitable for printing on the food packaging. The first part of the work is dedicated to the development of an UV ink for the generation of the stretchable optical waveguides. For the pattern to perform as an efficient waveguide, the contact angle of the printed patterns on the substrate should be close to 90°. The whole system was based on an ink consisting of a mixture of a vinyl ether and an urethane acrylate resin, and PDMS as substrate. To prove the functionality of the printed waveguides, the optical conductivity and the stretchability were tested. In the second part of this work a particle free silver ink to produce stretchable electronics was developed. Commercially available conductive inks are based on the silver nanoparticles or flakes. They require high sintering temperatures, which can damage the substrate. The ink developed in this work utilizes a modified Tollens reaction. A particle free formula that allows mild sintering temperatures of about 100 °C forms a silver nanoparticles-elestomer (Platilon®U) composite upon curing. The ink in the third part of the work was developed for the realization of biodegradable electronics. The work was motivated by a growing problem of the e-waste disposal. The recycling of the plastics used in electronics is problematic due to the presence of different additives, such as, e.g., flame retardants, and thus, a cellulose foil was tested as substrate. The ink was based on the 1-methylimidazol, which served as a solvent and complexing agent for the silver salt (silver acetate). A special procedure proceeding the UV curing allows the ink to penetrate the substrate and the printed pattern may exhibit conductivity across the cellulose foil. Furthermore, the biodegradability of the cellulose substrate was characterised by the enzymatic action of Cellulase T. Reseei. The fourth part of this work was a study on the design of UV curable water-based inkjet inks. The goal was to develop a low-migration system suitable for the printing on food packaging materials. For this purpose, thermally und UV-curable polyurethane dispersions were evaluated. In the course of the work, the mechanical properties of the cured inks in terms of the scratch resistance and the adhesion to the substrate, as well as pot life and printability of the chosen formulations were tested. In terms of the migration safety of the formulations, performance of the phototinitator Irgacure 2959 (Irg2959) and its cleavage products was characterised.

AB - Inkjet printing is a technique where a digital image is being reproduced on an even surface by depositing a vast amount of picolitre sized drops on the substrate. This method allows an easy and efficient printing of text and graphics, without the necessity for the impression cylinders or printing blocks. Thereby, there is a growing interest in this technology for the manufacturing of functional patterns in areas such as electronics, optics or life sciences. This work focused on the research and development of the inks for optics and electronics, and inks for graphics that are suitable for printing on the food packaging. The first part of the work is dedicated to the development of an UV ink for the generation of the stretchable optical waveguides. For the pattern to perform as an efficient waveguide, the contact angle of the printed patterns on the substrate should be close to 90°. The whole system was based on an ink consisting of a mixture of a vinyl ether and an urethane acrylate resin, and PDMS as substrate. To prove the functionality of the printed waveguides, the optical conductivity and the stretchability were tested. In the second part of this work a particle free silver ink to produce stretchable electronics was developed. Commercially available conductive inks are based on the silver nanoparticles or flakes. They require high sintering temperatures, which can damage the substrate. The ink developed in this work utilizes a modified Tollens reaction. A particle free formula that allows mild sintering temperatures of about 100 °C forms a silver nanoparticles-elestomer (Platilon®U) composite upon curing. The ink in the third part of the work was developed for the realization of biodegradable electronics. The work was motivated by a growing problem of the e-waste disposal. The recycling of the plastics used in electronics is problematic due to the presence of different additives, such as, e.g., flame retardants, and thus, a cellulose foil was tested as substrate. The ink was based on the 1-methylimidazol, which served as a solvent and complexing agent for the silver salt (silver acetate). A special procedure proceeding the UV curing allows the ink to penetrate the substrate and the printed pattern may exhibit conductivity across the cellulose foil. Furthermore, the biodegradability of the cellulose substrate was characterised by the enzymatic action of Cellulase T. Reseei. The fourth part of this work was a study on the design of UV curable water-based inkjet inks. The goal was to develop a low-migration system suitable for the printing on food packaging materials. For this purpose, thermally und UV-curable polyurethane dispersions were evaluated. In the course of the work, the mechanical properties of the cured inks in terms of the scratch resistance and the adhesion to the substrate, as well as pot life and printability of the chosen formulations were tested. In terms of the migration safety of the formulations, performance of the phototinitator Irgacure 2959 (Irg2959) and its cleavage products was characterised.

KW - inkjet

KW - printing

KW - ink

KW - optical

KW - waveguide

KW - electronics

KW - stretchable

KW - uv

KW - curable

KW - biodegradable

KW - Tintenstrahl

KW - Drucken

KW - Tinte

KW - optisch

KW - Wellenleiter

KW - Elektronik

KW - dehnbar

KW - UV

KW - Aushärtung

KW - biologisch abbaubar

M3 - Doctoral Thesis

ER -