H2SO4) for at least 20 min to ensure optimal adhesion and wettability. After cleaning them with deionized water and ethanol, they were dried in a nitrogen stream and placed on a heatable substrate holder (temperature: 60 °C) to ensure a fast curing of the printed lines with a high resolution. After printing, the structures were stored in a drying furnace at 90 °C in air to ensure a complete curing of the deposited material prior to its pyrolysis.