Virginia Tech lab 3D prints liquid metal composite with 40x thermal conductivity

A Virginia Tech lab mixed eutectic gallium-indium (EGaIn) into uncured PDMS silicone and 3D printed a composite that channels heat along stretched metal droplets. Thermal conductivity along the droplets reaches 9.9 W/mK, about 40 times that of the unfilled silicone. The material also self-heals conductive tracks.

• Composite: EGaIn (3 parts gallium to 1 part indium) in PDMS, droplets 10–100 microns
• Thermal conductivity of 9.9 W/mK along droplets, 40x higher than silicone
• Syringe-fed printing stretches droplets to direct heat from source to sink
• A cut conductive track reconnects when pressed, restoring the circuit