Self-Assembled Copper Film-Enabled Liquid Metal Core–Shell Composite

• Published in: ACS applied materials & interfaces Vol. 13; no. 50; pp. 60660 - 60671
• Main Authors: Yao, Yuchen, Chen, Sen, Ye, Jiao, Cui, Yuntao, Deng, Zhongshan
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 22.12.2021
• Subjects: Surfaces, Interfaces, and Applications; self-assembly; liquid metal; copper film; semiconductor; core−shell composite; phase change capsule; flexible electronics
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.1c18824

Liquid metal (LM) droplets covered with functional materials, especially metallic, often make breakthroughs in performance and functionality. In this study, self-assembly was used to synthesize copper films on the surface of LM. Herein, using CuO nanoparticles as the monomers, driven by the electrostatic interaction between CuO and eutectic gallium–indium (EGaIn) in the alkaline environment, EGaIn@Cu is realized by taking advantage of the reducing property of the EGaIn–alkaline interface. The copper film is smooth and dense, and under its protection, a layer of gallium oxide remains on the reaction interface between copper and LM, which enabled EGaIn@Cu to possess the volt–ampere curves similar to the Schottky mode, showing that the proposed mechanism has the potential to be used in the bottom-up synthesis of the semiconductor junction. Owing to the support of the copper film, the stiffness coefficient of the LM droplet can be increased by 56.9%. Coupled with the melting latent heat of 55.46 J/g and the natural high density of metal, EGaIn@Cu is also a potential phase change capsule. In addition, a method based on stream jetting and self-breaking up mechanisms of LM to batch-produce sub-millimeter capsules was also introduced. The above structural and functional characteristics demonstrate the value of this work in related fields.