Transient Emulsion-Assisted Fabrication of Liquid Metal Microsphere Arrays for Mechanically Adaptive Anisotropic Conductive Packaging

Abstract

Liquid metal (LM) microsphere arrays hold great promise as adaptive conductive frameworks for next-generation flexible electronics. However, the spatial arrangement of micronano LM droplets poses a longstanding challenge to their practical application due to their inherent ultrahigh surface tension. Here, we introduce a transient emulsion-assisted self-assembly and fusion strategy that turns surface tension from a barrier into a driving force for ordered LM microsphere formation and precise positioning. The resulting LM microspheres exhibit dynamic interfacial conduction, enabling excellent mechanical adaptability under deformation. Embedded into a thermally responsive polymer matrix, the fabricated LM microsphere-arrayed anisotropic conductive film (ACF) achieves an ultralow contact resistance (0.303 mΩ/mm², 96% lower than conventional ACFs) and stable performance under cyclic loading. Demonstrated in packaging flexible chip–LED arrays with stretchable circuits, this approach ensures both mechanical resilience and electrical reliability. This work offers a scalable pathway toward high-performance, compliant interconnects for future soft electronic systems.