Here is the abstract you requested from the Additive_2016 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Development and Characterization of Conductive Jettable Inks|
|Keywords: particle-less inks, inkjet printing, characterization methods|
|Interest in printed circuits, sensors, electronics and radio frequency identification tags via liquid-based ink has grown in recent years. By using functional fluids, inkjet printing technology is a promising method to deposit patterned metallic thin film structures on polymer substrates for use as electrical contacts, circuit elements or sensory elements. Our laboratory has specialized in development of new inks as well as standardized characterization of the ink’s physical parameters to ensure reliability and reproducibility of the printed structures. While various companies produce a wide variety of metallic inks, data sheets for the inks do not necessarily specify essential ink properties such as particle size, morphology, and distribution, resistance, surface tension, viscosity, optimal printing and curing parameters, visible color, density, and several other properties. Consequently, comparisons of ink specifications from different vendors can be difficult. To solve these problem, our lab has been designing a set of standardized tests for evaluating key ink properties that are commonly evaluated when deciding which inks would be best suited for a specific project. In this presentation, we also highlight two inks which we have developed: a particle-free silver ink and a water-based constantan ink. The particle-free silver ink exhibits a sheet resistivity of 3.1 μΩ∙cm). Due to the absence of particles, this particle-free silver ink exhibits essentially no clogging problems with most inkjet applications. Constantan ink is also developed which has excellent potential in mechanical sensing applications due to constantan’s small temperature coefficient of resistivity. Using a design chemical process, a stable constantan ink is formulated and constantan patterns are fabricated by inkjet printing. This simple process can remove/reduce surface oxidation of constantan and sinter high melting temperature constantan alloy nanoparticles at relative low temperature without flammable reducing gas. The composition of sintered constantan film is confirmed by XRD and XPS. Scanning electron microscopy shows the designed chemical process can anneal constantan nanoparticles effectively after sintering for 2 h at 250 ℃ in vacuum. The printed constantan patterns exhibit a resistivity within about a factor of 10 and essentially the same temperature coefficient as bulk constantan.|
|Michael Carr, PhD Student - Research Assistant