Surface engineering via self-assembly on PEDOT: PSS fibers: Biomimetic fluff-like morphology and sensing application

Wearable sensors based on fibers or textiles are attracting widespread attention due to their potential applications in wearable health monitoring and care systems, where high sensitivity plays an essential role in the development of electroconductive fibers. Though the great progress has been made in designing novel structures and understanding sensing mechanism, how to prepare conductive fibers with high sustainability and conductivity via a facile and efficient method is still a challenge. Herein, inspired by the spider’s fluff, an ion-induced self-assembly is proposed and performed to obtain continuous and large-scale fabrication of poly (3, 4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS) fibers with an array microstructure. The formation of copper complex with fluff-like shape occurs spontaneously on the surface of PEDOT fibers without any additional post-treatment or harsh condition, which is difficult to achieve by other approaches. Benefiting from the fluff-like array, these biomimetic PEDOT: PSS-Cu2+ fibers possess a near 5-fold increase in specific surface area compared to that of pristine PEDOT: PSS fibers, which endows it with a good pressure sensitivity with ultralow detection limit (~82 Pa) and fast response time (47 ms). We further demonstrate their potential applications for airflow detection, real-time information transmission, and gravity/pressure sensing while decorating such biomimetic fibers to braided fabrics. More importantly, this work sheds light on the formation mechanisms of microstructures on the fiber, inspiring a unique path for conventional wet-spinning technology and novel fiber-surface design in order to achieve its outstanding sensitivity.