Wax-shaped wettability assisted patterning of silver nanowires on various substrates as transparent, flexible, or stretchable electrodes

With the rapid development of flexible and wearable devices, flexible transparent conductive electrodes are highly demanded. However, there is no available technology that can pattern emerging electric materials (e.g., silver nanowires (AgNWs)) on versatile substrates in large scale to achieve high performance in different aspects on demands, such as transparency, flexibility, stretchability, and biocompatibility. Here, a wax-shaped wetting/dewetting (WSWD) method is demonstrated to pattern AgNWs networks into transparent conductive circuits ranging from tens of micrometers to centimeters on various substrates. For instance, the AgNWs coatings patterned on polyethylene terephthalate (PET) films achieve high electrical conductivity and optical transparency up to 73%, and a stable resistance (CV < 0.1%) after cyclic bending (>200 times); the AgNWs coatings patterned into polydimethylsiloxane (PDMS) microchannels exhibit good durability after cyclic bending (>200 times) and stretching (30% strain). Finally, the flexible AgNWs coatings are used as wearable transparent heaters applied to the human finger joint and wrist, which are thermally stable and safe (42 °C < T < 50 °C for 3 min) under cyclic bending. Thus, this method provides a simple, low-cost, green, and versatile means for fabricating transparent conductive electrodes, which can be applied to optoelectronic, wearable, and healthcare devices.