Work

Freeform 3D Printing of Omnidirectionally Deformable Conductors via Newtonian Liquid Metal Droplet‐Mediated Stress Relaxation

Year: 2026

Type: article

Abstract: ABSTRACT Next‐generation soft robotics and shape‐morphing electronics demand materials that possess intrinsic softness yet processable into freeform 3D architectures. However, direct‐write 3D printing of soft elastomers suffers from a rheological trade‐off, where high yield stress required for printability increases stiffness. This work presents a ternary silicone elastomer ink that breaks this limitation by incorporating liquid metal (LM) as a Newtonian liquid filler. The fluidic LM droplets act as stress buffers, accelerating stress relaxation during flow without compromising post‐curing compliance. Additionally, they induce an excluded‐volume effect that increases the effective local concentration of the dispersed multi‐walled carbon nanotubes (MWCNTs), thereby enhancing the percolating conductive network. This strategy enables support‐free 3D printing, achieving maximum bridging spans of 32 mm and a peak resolution of 124 µm independently. The composite exhibits high stretchability (446% elongation), a bulk conductivity of 7.08 S/m, and electrical stability under large deformation (∆R/R 0 = 0.51 at 100% strain). The versatility of this platform was further validated through reconfigurable 3D circuits, demonstrating that in addition to functioning as compliant conductors, the printed structures can also serve as robust load‐bearing structural elements. By reconciling printability, softness, and deformation‐tolerant electrical conductivity, this work establishes a general approach for freeform 3D soft electronics.

Source: Advanced Functional Materials

DOI: 10.1002/adfm.79487