Ohmic Curing of Silver Micro-Particle Inks Printed on Thermoplastics

The ohmic curing of two silver micro-particle inks was studied. Silver lines of 35 to 75 µm thick were printed on a mixture of polycarbonate and acrylonitrile butadiene styrene (PC+ABS) substrate and on a mineral reinforced Nylon 6 thermoplastic, using a laboratory-made system based on a volumetric dosing dispenser. After 48 h of stabilization in ambient conditions, a current is applied through the printed lines with an imposed intensity value and application time in order to cure the silver inks. Evolutions of the temperature and the resistivity of silver tracks were followed during the process. Printed thermoplastics were characterized at the end of the process in order to check the absence of deformation due to the curing treatment. The study showed that the ohmic curing led to better electrical performances than an oven process with a considerable time saving. Most of the printed line resistivity drop occurred in the first 30 s of the treatment. The ohmic curing induced a local increase of temperature located in the printed line and avoided damaging the substrates, which makes the process compatible with thermal sensitive substrates. Therefore, the ohmic curing is an efficient low-cost process to cure silver micro-particle inks that could be easily implemented at an industrial scale.