Emine Tekin

Inkjet printing as a deposition and patterning tool for polymers and inorganic particles

Inkjet printing is an attractive patterning technology, which has become increasingly accepted for a variety of industrial and scientific applications. This review primarily presents an overview of the investigations that have been conducted since 2003 into inkjet-printing polymers or metal-containing inks and mentions related activities. The first section discusses the droplet-formation process in piezoelectric drop-on-demand printheads and the physical properties that affect droplet formation and the resolution of inkjet-printed features. The second section deals with the issues that arise from printing polymers, such as printability and the output characteristics of devices made by this route. Finally, the challenges and achievements attached to inkjet printing metal-containing inks are discussed before concluding with a few remarks about the future of the field.

Ink-jet printing of polymers – from single dots to thin film libraries

Recent results on the ink-jet printing of polymer films are presented. Films that were printed using an ink-jet process based on one single solvent always suffered from ring formation, i.e. the coffee-drop effect. This drawback could be overcome by the use of solvent mixtures. The effects of solvent mass ratio, print head velocity, dot spacing and printing method were investigated and optimized to reproducibly obtain homogeneous polymer films (6 × 6 mm size). The results obtained represent an important step towards the application of ink-jet printing for the controlled deposition of polymer dots and libraries.

Film thickness dependency of the emission colors of PPE–PPVs in inkjet printed libraries

The influence on the emission color of π-conjugated polymers varying side chains, film thicknesses and thermal treatment were investigated in a parallel fashion. The respective thickness libraries of six alkoxy-substituted poly(p-phenyleneethynylene)-alt-poly(p-phenylenevinylene)s (PPE–PPVs) were prepared by inkjet printing in a controlled way. The optical properties of the printed libraries were screened utilizing high-throughput methods. It was found that the emission colors of the investigated polymers strongly depend on the inter-chain interactions which are increased with increasing film thickness and influenced by the side chains. Moreover, upon annealing at 70 °C, white emission was observed from the printed films.