Shear-enhanced Liquid Crystal Spinning of Conjugated Polymer Fibers

TL;DR

This paper presents a shear-induced liquid crystal spinning method to produce mechanically strong, anisotropic conjugated polymer fibers with enhanced semiconductor and electrochemical properties, suitable for wearable electronics.

Contribution

It introduces a novel shear stress technique to regulate pi-pi stacking in conjugated polymers, enabling continuous fabrication of high-performance fibers with industrial relevance.

Findings

Fibers exhibit high mechanical strength of 600 MPa.

Fibers maintain stability under extreme conditions.

Successful demonstration of fiber-based organic electrochemical transistors.

Abstract

Conjugated polymer fibers can be used to manufacture various soft fibrous optoelectronic devices, significantly advancing wearable devices and smart textiles. Recently, conjugated polymer-based fibrous electronic devices have been widely used in energy conversion, electrochemical sensing, and human-machine interaction. However, the insufficient mechanical properties of conjugated polymer fibers, the difficulty in solution processing semiconductors with rigid main chains, and the challenges in large-scale continuous production have limited their further development in the wearable field. We regulated the pi - pi stacking interactions in conjugated polymer molecules below their critical liquid crystal concentration by applying fluid shear stress. We implemented secondary orientation, leading to the continuous fabrication of anisotropic semiconductor fibers. This strategy enables conjugated polymers with rigid backbones to synergistically enhance the mechanical and semiconductor properties of fibers through liquid crystal spinning. Furthermore, conjugated polymer fibers, exhibiting excellent electrochemical performance and high mechanical strength (600 MPa) that essentially meet the requirements for industrialized preparation, maintain stability under extreme temperatures, radiation, and chemical reagents. Lastly, we have demonstrated logic circuits using semiconductor fiber organic electrochemical transistors, showcasing its application potential in the field of wearable fabric-style logic processing. These findings confirm the importance of the liquid crystalline state and solution control in optimizing the performance of conjugated polymer fibers, thus paving the way for developing a new generation of soft fiber semiconductor devices.