Solution-Processable, Elongated Liquid Metal Particles for Composites with Enhanced Thermal Management

The natural tendency of liquid metal (LM) droplets to minimize surface energy and form spherical shapes presents a fundamental challenge for synthesizing elongated LM particles in solution. Overcoming this limitation is critical for the development of anisotropic functional materials with potential applications in stretchable electronics and wearable devices. To address this challenge, a solution-based method is presented to synthesize stable, elongated particles of eutectic gallium-indium (EGaIn) by combining a high-intensity mixing process with particle surface modification. Various surface modification agents are investigated, and the elongated LM particles are incorporated into uncured elastomers. In particular, polyvinylpyrrolidone (PVP)-functionalized EGaIn particles retain their high aspect ratio after embedding in silicone elastomers. Furthermore, these elongated particles are aligned within the elastomer matrix via printing and doctor-blading techniques, producing composites with anisotropic internal microstructures. The resulting LM-elastomer composites exhibit enhanced heat dissipation and thermal conductivity compared with isotropic counterparts, with numerical simulations confirming the role of the elongated particle morphology. Beyond thermal management, the elongated, solution-processable LM particles serve as programmable liquid-state functional units compatible with diverse polymer matrices and fabrication methods.