Continuous, green, and room-temperature synthesis of silver nanowires in a helically-coiled millifluidic reactor

Over the past decade, silver nanowires (AgNWs) have been considered as promising alternatives for manufacturing flexible and transparent conductive films used in the production of various electronic and wearable devices. Nevertheless, the continuous and large-scale synthesis of AgNWs without the use of highenergy methods and hazardous reagents can be challenging. In this study, we report the continuous, green and sustainable synthesis of AgNWs at room temperature in a helically-coiled plug flow millifluidic reactor, using tannic acid as an environmentally-friendly reducing and capping agent. The synthesized AgNWs were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-visible spectroscopy (UV-Vis). We have showed that the presence of silicone oil and triton X-100 is necessary for the undisturbed synthesis of AgNWs. We further demonstrated that AgNWs synthesized in the millifluidic reactor had a higher yield (by 32%) compared to those synthesized in batch condition. We further showed how the synthesis of AgNWs can be affected by exposure to UV-visible light. Finally, we investigated the effect of coil diameter on the consumption of Ag+ ions, the morphology of silver nanostructures, and the yield of AgNWs. The proposed approach can serve as a promising technique for the continuous synthesis of AgNWs and further green and sustainable manufacturing in the field of nanomaterials synthesis.