Scientists from the Nanjing University of Posts and Telecommunications have devised a simple, scalable and low-cost capillary-driven self-assembly method to prepare silver nanowires (Ag NWs) coated flexible and stretchable conductive fibres that have applications in wearable electronics and smart fabrics. The paper is to be published in Nano.

These conductive fibres have uniform morphology, high conductivity and good mechanical strength.

The research has been carried out by Dr. Yi Li and Yanwen Ma, from the Key Laboratory for Organic Electronics and Information Displays, Institute of Advanced Materials (IAM) of Nanjing University of Posts and Telecommunications and his collaborators.

Taking advantage of the capillary action of fibres, such as cotton, nylon and polyester yarns as well as PDMS fibres, the solution containing Ag NWs is spontaneously absorbed into the capillary tunnels. Then Ag NWs are evenly coated onto the fibres through evaporation-induced flow and capillary-driven self-assembly process to form conductive fibres, which is in situ observed by the optical microscopic measurement. The fabricated flexible and stretchable conductor exhibits uniform morphology, high conductivity and good mechanical strength, which is promising for the application in wearable electronics and smart fabrics.

Conventional conductive fibres are metal wires such as stainless steel and copper wires, as well as the metal film coated yarn. These conductive fibres are stiff and brittle, not meeting the demand of flexibility and comfortability for smart textiles.

Smart textiles with electronic devices such as sensor, light emitting diode, transistor, battery and supercapacitors integrated into fabrics have drawn considerable attention. Conductive fibres and yarns, with the function of connecting various electronic devices, play a key role in smart textiles system. Recently, conductive nanomaterials such as metal nanomaterials, carbon nanotubes and graphene with high conductivity, good mechanical properties, feasibility of large-scale production and solution-process, have become a new type of fundamental materials for conductive fibres. Great efforts have been made to engineer conductive nanomaterials into conductive fibres by various technologies such as vapour deposition, electrospinning and spray coating methods. Despite these promising progresses, the facile, large-scale and cost-effective fabrication of conductive fibres with high flexibility and good electrical conductivity is still a challenge.

This work was partially funded by National Natural Science Foundation of China and Keypoint Research and Invention Programme of Jiangsu Province. (SV)