Tuneable electrochromism in weavable carbon nanotube/polydiacetylene yarns

Weavable color-change materials are useful in smart textiles. Here we demonstrate static and programmable color change on flexible polydiacetylene (PDA) coated carbon nanotube (CNT) yarns through 3D hopping-conduction-induced electrochromism. The color change could be achieved using pre-patterning and further specified through defining the current paths. Mild heating before polymerization was used to gain control over the critical transition voltage and ZnO nanoparticles were introduced to anchor PDA and facilitate reversibility of the electrochromic transition. In-situ absorbance and Raman spectroscopy, Raman mapping and surface characterization with X-ray spectroscopy revealed that mild heating increased the critical transition voltage while PDA anchoring on ZnO improved the reversibility. The ability to tune CNT/PDA electrochromism through inexpensive structural alterations is promising for applications in smart textiles where complex patterns can be instantaneously realized and controlled with electrical stimulus.