Fabrication of Stretchable and Conductive Liquid Metal Microfibers through Coaxial Emulsion Electrospinning

Liquid metal fibers are increasingly used in soft multifunctional materials and soft electronics due to their superb stretchability, high conductivity, and lightweight. This work presents a systematic study of the electrospinning process of liquid metal microfibers. Compared to other methods that usually produce fibers thicker than 100 mu m, electrospinning is a facile and low-cost method of producing liquid metal fibers in the range of 10-100 mu m. Specifically, core-sheath liquid metal microfibers are fabricated with a highly conductive liquid metal core and a super-stretchable thermoplastic elastomer sheath. This manufacturing process uses a liquid metal emulsion as the core solution, which circumvents manufacturing failures caused by the high surface tension of liquid metals. The influence of key processing parameters such as core flow rate, sheath flow rate, and applied voltage on the fiber diameter and morphology is studied by experiments. The mechanical and electrical properties of the as-fabricated liquid metal microfibers, mats, and yarns are tested and discussed.