Microdroplet splitting and mixing by portable triboelectric nanogenerator

The advancement of digital microfluidics technology has been pivotal in academic research and engineering applications. However, the prevailing limitation is that traditional voltage sources generate an excess of Joule heat, adversely impacting droplet operation. Moreover, the power supply equipment required by digital microfluidics limits its applications. Here, we propose a self-powered microdroplet manipulation (SMDM) via triboelectric nanogenerator (TENG), which presents a capability for splitting and mixing different kinds of droplets. Fundamentally, SMDM is based on the electroosmotic flow principle, thereby enabling droplet splitting in the range of from 2 to 630 μL. Notably, for droplet splitting in the range of from 5 to 60 μL, the TENG only requires a power output ranging from 2.704 to 6.084 mW. In addition, SMDM demonstrates proficiency in droplet mixing, which achieves complete mixing of 10 μL droplets in 60 s and 30 μL droplets in a mere 53 s. Therefore, leveraging the strengths of the TENG, a self-powered microdroplet manipulated system is designed for digital microfluidics. It carries significant advantages over the traditional voltage source, including self-powered, low-Joule heat, increased safety and enhanced portability. This research provides a new solution for portable applications of digital microfluidics.