Ultrasonic-prepared porous CuGa₂ alloy for efficiently removing undesired room-temperature liquid metals from various substrates

Abstract An efficient and reusable ‘sponge’ based on a porous CuGa 2 alloy (PCA) is developed for removing excess or unwanted room-temperature liquid metals (RTLMs), such as Ga and its room-temperature alloys, from various substrates. PCA is easily prepared using an ultrasonic-enhanced wet/alloy strategy, where Ga penetrates and reacts with the copper foam substrate. The RTLM absorption is highly correlated with the pore density and volume of hydrochloric acid in the PCA. By regulating the pore density and volume of hydrochloric acid, PCA exhibits high RTLM removal efficiencies on different material surfaces, namely wood, nitrile gloves, plastic, and glass. For PCA (1.5 cm × 1.0 cm × 0.3 cm) with 300 pores per linear inch and 40 μl of hydrochloric acid, the strongest liquid Ga adsorption capacity is observed, and the maximum weight gain reaches approximately 352 ± 4% after absorption. The high removal efficiency of PCA is attributed to its high wettability with RTLM and high capillary adsorption capacity. Furthermore, PCA is very economical; it can be recycled and reused without losing its RTLM adsorption capacity or mechanical strength. Herein, the convenience of using PCA is demonstrated in LED circuit editing, highlighting its potential in flexible electronics applications.