Professors Ying Sun of the Drexel University Mechanical Engineering and Mechanics Department and Christopher Li of the Materials Science and Engineering Department were awarded a grant by the National Science Foundation to investigate using Janus Nanoparticles to develop improvements in low-cost, high-output inkjet methods for printing functional nanoparticles on to flexible substrates.
Many everyday electronic devices are made using a batch-based photolithography processes that involves wet-chemical etching. An alternative manufacturing route exists for producing low-cost consumer electronics, large-area solar cells and smart sensors is through roll-to-roll printing technology. In printable electronics, electrical or optical inks are “printed” on to thin, flexible sheets of material, similar to printing a newspaper. However, current graphic printing technology is incapable of producing nano-sized features and well controlled patterns due to “coffee ring effect.”
Sun hopes that Janus Nanoparticles might offer a "decaffeinated" solution. Janus Nanoparticles are asymmetric particles with two different surface chemical compositions. These unique particles allow for two different types of surface properties to occur within the same particle and have shown their ability to suppress the “coffee ring” formation. This suppression may lead to improved resolution during printing. Janus Nanoparticles can be “tuned” to orient themselves in a particular manner. Tuning would allow researchers to direct the self-assembly of nanoparticles into a desired structure.
Sun and Li believe that using Janus particles as tunable building blocks opens the door to a large class of smart membranes for energy applications and might enable environmentally-benign, large-area inkjet printing processes for the production of next generation of flexible electronics, a potential technological breakthrough far beyond what current printing technologies can offer.
Sun and Li were awarded $250,001 for their NSF proposal titled, Scalable Capillary-Driven Assembly of Asymmetric Nanoparticles via Inkjet Printing.