Scalable Production of MXene Dip-Coated Yarns and Cords

Fibers, yarns, and textiles have long established themselves in many sectors of society from our daily wear to medicine and structural composites. The rise of the Internet of Things (IoT) has prompted incorporation of conductive materials into textiles that enable real-time monitoring of external stimuli (e.g., stretch, pressure, temperature, and humidity) and body responses. Sensors, antennas, energy storage sources need to be incorporated into textiles. New functions, such as IR stealth, EMI shielding or passive and active temperature control, can be enabled by conductive or optically active coatings. Among the many conductive materials and fabrication methods demonstrated, few met the performance and cost requirements of real-world applications. MXenes are an emerging class of 2D nanomaterials that possess excellent electrical conductivity, attractive optical/plasmonic properties, solution processability and hydrophilic surfaces, making them ideal for imparting conductivity to textiles in a simple dip coating fashion. In this work, a high throughput continuous coating method was demonstrated with a customized automatic yarn dip coater. Thanks to the shear force present in the dip coater and the preferred interactions between Kevlar and MXene, viscous MXene solutions and fast coating speeds could be used. Kilometers of highly conductive MXene coated Kevlar cords were produced with consistent quality. Tensile test with <i>in-situ</i> electrical resistance tracking showed the multifunctionality of Ti₃C₂T_x coated Kevlar for composites, both as structural reinforcement and damage sensing.