Real-time coloration control of gallium-based strips through cold rolling

Cold rolling has been used as a real-time surface oxidation control method to create colored strips on flexible substrates. By controlling the extrusion rate in real time, a variety of colored strips have been fabricated on Ga-based liquid metal (LM) strips. X-ray photoelectron spectroscopy (XPS) analysis shows that the surfaces of the colored strips, which were obtained through extrusion rate control of LM-Al, consist primarily of metal oxide composites, including Ga₂O₃, Ga₂O, Al₂O₃, SnO₂, and In₂O₃. The colors of the strip surfaces are directly correlated with the oxide film thickness. Additionally, these cold-rolled colored thin strips demonstrate high conductivity and have significant potential for use as conductive flexible components with indicator functions in the flexible electronics realm.