Biomimetic spinning of soft functional fibres via spontaneous phase separation

Soft fibres can be used to make smart textiles for use in energy, sensing and therapeutic applications. However, the fabrication of functional fibres is difficult compared with the fabrication of two-dimensional films and three-dimensional monoliths, and current methods typically require high temperatures, high volumes of solvents or complex systems. Here we report a spinning approach to fabricate functional fibres, which is based on spontaneous phase separation and is inspired by the silk-spinning processes of spiders. The silk-spinning process is mimicked by creating a spinning solution of polyacrylonitrile and silver ions, which forms an elastic supramolecular network with silver coordination complexes and in situ reduced silver nanoparticles. This approach, which operates at ambient pressure and temperature, can be used to make soft functional fibres that are mechanically stretchable (more than 500% strain), strong (more than 6 MPa) and electrically conductive (around 1.82 S m −1 ). To illustrate the capabilities of the technique, we use the fibres to create a sensing glove and a smart face mask.