An electrochromic alginate fiber based on a WO/PEDOT:PSS composite layer.

In this experiment, we studied a technique that permits the continuous fabrication of electrochromic alginate fibers because there hasn't been much research on electrochromic alginate fibers. Therefore, it's important to investigate ways to increase the application areas of alginate fibers. AgNP‑calcium alginate fibers with high electrical conductivity were prepared by Ag substitution method. Electrochromic alginate fibers were successfully prepared by sequentially coating the fibers with PEDOT:PSS, WO, and PVDF:HFP to form a WO/PEDOT:PSS composite color-changing layer and a PVDF:HFP stable electrolyte layer. Fifty electrochromic alginate fibers with a length of 7 cm were tested, and their resistance values ranged from 2 to 12 Ω, of which 78 % were between 3 and 8 Ω, providing excellent electrical conductivity. In the electrolyte from 0.1 V to -0.7 V, the color of the fiber changes from the original state to the colored state in only 5 s. Ten minutes after the voltage is disconnected, the color changes to the original color of the AgNP-Calcium Alginate fibers and the color change are reversible. The solid fibers can change from light blue to dark blue and the color change is uniform in the upright and bent state. This study lays a solid research foundation for the industrial production and intelligent application of electrochromic alginate fibers.