Abstract
Direct ink writing (DIW) is one of the advanced additive manufacturing (AM) fabrication method that enables the use of a wide range of materials, including ceramics, thermoset and thermoplastic polymers, biomaterials. For good electrical conductivity, the polymer composites may contain conductive particles dispersed in the matrix, while high particle loading compromises the flexibility of the composites. It has been demonstrated that combining liquid metal (LM) like eutectic gallium alloy and/or galinstan with an elastomer like polydimethylsiloxane (PDMS) retains conductivity and flexibility. However, dispersing the LM in a silicone-based elastomer such as Ecoflex, which offers variants with different stiffness for DIW of multiple layers remains an open issue. Herein, our goal is to investigate LM compositions based on the galinstan-loaded ecoflex composite for DIW of the conductive structures. One of the most critical concerns for DIW 3D printing of viscous material is the solid-like recovery followed by discharge of the ink. The effect of rheological properties of the ink and DIW parameters (such as nozzle size, pressure, and speed) on print fidelity was examined. Using the composite ink and identified printing parameters, a simple conductive fibre was 3D-printed and its mechanical and electrical properties were evaluated.