Simultaneous Embedding and Welding of Silver Nanowires Into the Surface of Polymer Networks for Mechanically Robust and Highly Conductive Three-Dimensional Flexible Transparent Electrodes.

Three-dimensional (3D) flexible transparent electrodes (FTEs) with high conductivity and mechanical robustness are essential for high-performance wearable optoelectronic devices. Silver nanowires (AgNWs) are attractive candidates for the FTEs due to their high transparency, flexibility, and conductivity; however, poly(vinylpyrrolidone) (PVP) coatings on AgNWs and poor contact at wire junctions increase resistance. Additionally, electrodes fabricated using conventional AgNW deposition methods exhibit poor adhesion between the AgNW layer and polymer surface, resulting in delamination and degraded electrical performance under repeated stimuli. Herein, we propose a transfer method that simultaneously welds and embeds AgNWs into the surface of thermally stable thermoset polymer networks. Thermal annealing (200°C, 1 min) welds AgNW junctions while curing the prepolymer, forming mechanical interlocking that anchors AgNWs in the polymer surface. This enables residue-free transfer and fabrication of highly conductive, mechanically robust FTEs while maintaining optical transparency. The FTEs exhibited stable performance after 1000 bending cycles (radius of curvature = 3.5 mm) and 5000 pressure cycles at 70 kPa. Capacitive pressure sensors incorporating these FTEs demonstrated reliable performance, while enhanced conductivity enabled efficient Joule heating, reaching 42.9°C at 3.7 V, demonstrating suitability for wearable heaters. These confirm the proposed method as a reliable approach for high-performance 3D FTEs.