A general finite-gel strategy for highly concentrated liquid metal inks.

Producing high-concentration liquid metal (LM) inks is highly desirable for next-generation flexible electronics, and yet remains a dulling challenging due to the large surface tension and high density of LM droplets. Herein, a general finite-gel strategy is proposed to enable the fabrication of high-concentration liquid metal (LM) inks. In the LM-based inks, the LM droplets are confined in the relaxed finite-gel networks, which provide strong repulsive effects to avoid the reunition of the adjacent LM droplets. The unique structure imparts the LM-based inks with a good colloidal stability even at a very high LM concentration of 30,000.0 g/L. The LM-based inks also present tunable rheological behavior and are suitable for various processing technologies. Moreover, the proposed finite-gel strategy is scalable, and could be expanded to various cryogel systems (e.g., curdlan, gelatin, and gellan gum). This work takes a crucial step forward to producing highly concentrated LM-based inks for flexible electronics.