A research team led by Professor Wu Hao and Academician Yin Zhouping from the School of Mechanical Science and Engineering at Huazhong University of Science and Technology (HUST) published its findings on flexible electronics in Nature Communications on Aug 17.

The paper, titled "High-performance stretchable conductive film on complex microscale structures via spontaneous fusion of liquid metal", lists PhD students Zhou Sen and Pang Bo as co-first authors. Professor Wu Hao served as the corresponding author, and HUST’s Bu Tianzhao and Professor Wu Changsheng from the National University of Singapore served as co-corresponding authors. Academician Yin Zhouping and others are listed as co-authors.

Conformal fabrication of stretchable conductive films on microstructured surfaces is essential for extending flexible electronics into emerging fields such as health monitoring, robotic perception, and human–machine interaction. Existing strategies, which rely mainly on materials design or structural engineering, struggle to balance stretchability, conductivity, and geometrical compatibility. With metallic conductivity and liquid-like deformability, liquid metals are regarded as an ideal material system for stretchable conductors. However, liquid metal–based composites typically require additional activation steps to interconnect the liquid metal particles, which restricts their applicability to substrates with complex geometries. As a result, although existing methods can pattern planar or low-curvature surfaces, conformal deposition on complex microstructured surfaces remains a significant challenge.

To address this challenge, the research team proposed a novel strategy for spontaneous fusion of liquid metal without external activation. When the surface of the liquid metal particles is hydrophilized, liquid bridges can form naturally between adjacent particles. During evaporative drying, the liquid bridge force spontaneously exceeds the critical rupture strength of the particle shells, driving the particles to self-fuse into a continuous conductive film. This technique supports simple spray-based fabrication and can be applied to a variety of three-dimensional (3D) microstructures and curved biological surfaces.

The resulting conductive film demonstrates strong adhesion to the substrate, extreme deformability, excellent strain insensitivity, good antibacterial properties, and biocompatibility. Stretchable multilayer electronic systems built with this strategy can stably output high-frequency signals and perform signal acquisition and serial communication even under continuous stretching deformation. Ultrasoft epidermal electrodes directly fabricated on human skin conform to fine microscopic textures, allow for breathable, imperceptible wear, and enable high-precision physiological signal acquisition.

This spontaneous fusion strategy for liquid metals enables the fabrication of high-performance stretchable conductive films on complex 3D microstructures, with promising applications in flexible electronics, medical health monitoring, and related fields.

Source: School of Mechanical Science and Engineering, HUST