Nano-Inks for 3D Printing

The global demand for nano inks for 3D printing is drastically rising for printed and flexible electronics, sensors, bio-medical, energy storage, and harvesting-based applications. The market for these inks ranges from metal nanoparticles (NPs) as well as carbon-based inks. The functional properties of the inks depend on the synthesis method for the NPs and their formulation technique of concentrating them into ink form. These inks can be deposited on different substrates through different deposition techniques such as sputtering, CVD, lithography, etc. But, due to its costly, laborious, and time-consuming process, 3D printing is offering zero-waste manufacturing with minimal running cost and high prospects for large scalability. The usability of these nano inks in 3D printing techniques such as inkjet and extrusion printing methods requires a complete fluid rheological and dynamic study that helps in choosing and optimizing the ink concentration, surfactant, and type of solvent. Therefore, this book chapter discusses in depth the basics of different synthesis methods for these inks, challenges in formulation, and its rheological and jettability characterization framework with the help of dimensionless numbers. It also comprises a detailed review of different types of inks ranging from metallic (gold (Au), silver (Ag), and copper (Cu) NPs) to carbon-based inks of graphene/reduced graphene oxide (rGO), carbon nanotubes (CNTs), and their hybrid forms.