Abstract
Environmental, social, and governmental factors have received increased attention in the design and manufacture of electronics. Additive printed electronics processes reduce the waste streams from electronics manufacturing by eliminating plate and etch processes, which involve the selective removal of masks and conductive copper to fabricate circuits. In addition, the transition to additive print processes also allows for the elimination of hard tooling, with design changes limited to those that can be implemented quickly, reducing the time involved with design iterations. The earlier versions of additive inks involved using volatile solvents as carrier mediums for nanoparticle inks. Sustainable inks use water as the carrier medium in place of volatile solvents. Owing to the recent introduction of these formulations, less is known about the ability to form functional circuits with sustainable inks or their performance relative to the incumbent non-sustainable volatile organic solvent-based inks. In this paper, the performance of sustainable water-based solvent inks has been studied and compared with that of volatile solvent inks. The Aerosol Jet printer was used in this work to print and develop process parameters for investigation, including ultrasonic atomizer mass flow rate, sheath flow control, and stage speed, with a water-based sustainable silver nanoparticle ink. Electrical and mechanical properties were tested at various sintering temperatures and times, including resistance and shear load to failure. The results show that the electrical properties are improved by varying these parameters, and optical methods have also been used to characterize the results of the printed trace and fitted regression models that have been developed for process optimization.
