Process and Material Characterization in Printed Flexible Electronics

Abstract

Integration of additive manufacturing (AM) and 3D printing technologies with electronics fabrication processes have achieved better advancement in the electronics industry. In additive manufacturing or 3D printing of flexible electronics, for instance, the fabrication process and design of the structures and functional components strongly affect the material properties and device performance. This is especially critical for novel and innovative structures that approach the limit of what is possible nowadays, such as stretchable and wearable electronics or adaptive structures in 4D printing. It is therefore crucial to include the material characterization in the design loop: material properties can differ due to build orientation (anisotropy), size of the object (scaling), and many other factors. The typical materials used in AM or 3D printing are polymers, metals, ceramics, and composites (as well as biomaterials). The raw materials used can be broadly classified based on their forms in either liquid, solid, or powder. The aims of this chapter are to address the most efficient characterization methods for 3D printing processes, characterization of AM and 3D printable materials through testing, and material models that can be used in process design and optimization methods to develop durable flexible electronics.KeywordsMaterial characterizationInkjet printingNewtonian fluidViscosityViscoelasticityRheologySurface tensionJettabilityCuringSintering