Highly conductive-sensitive, single-walled carbon nanotubes–poly(3,4-ethylenedioxythiophene) polystyrene sulphonate-coated cotton thread for thermally stable fabric and wearable e-textiles

There is an increasing insistence on smart, flexible devices that can be worn, based on carbon materials, nanomaterials and new polymers, as there are machines that mimic human movements, such as soft robotics, human interface machines and flexible sensing uses. In the present article, the development of textile threads of cotton, coated with single-walled carbon nanotubes (SWCNTs) and poly(3,4-ethylene dioxythiophene) polystyrene sulphonate (PEDOT:PSS) by dip-coating method is presented. Dip-coating is a simple, inexpensive and upgradable process. SWCNTs and PEDOT:PSS were coated on the cotton threads to fill the gaps within the hierarchical structure of the threads. Non-polar organic solvent dimethyl sulphoxide was used as a reducing agent, which increased the density of the SWCNTs and PEDOT:PSS moieties on the filament. This increased the electrical conductivity. Due to this combination, electrical paths increased, decreasing the electrical resistance. The formation of a fine film of conductive materials on the threads was observed by scanning electron microscopy, while Fourier infrared spectroscopy and X-ray diffraction were used for structural analysis. Fabrics, being planar materials, enable easy measurement of surface resistivity to understand their electrical behaviour and related performance. Hence, a four-line probe method was used to study the conducting stability of the treated cotton sutures. Thermogravimetric analysis revealed that the temperature at which the treated thread had its maximum rate of weight loss increased by about 20°C with respect to the original thread. Moreover, as an alternative to a metal wire, the treated thread has an advantage of being light in weight and has high conductivity.