Carbon Nanotube‐Directed 7 GPa Heterocyclic Aramid Fiber and Its Application in Artificial Muscles

Abstract

Poly(p‐phenylene‐benzimidazole‐terephthalamide) (PBIA) fibers with excellent mechanical properties are widely used in fields that require impact‐resistant materials such as ballistic protection and aerospace. The introduction of heterocycles in polymer chains increases their flexibility and makes it easier to optimize the fiber structure during spinning. However, the inadequate orientation of polymer chains is one of the main reasons for the large difference between the measured and theoretical mechanical properties of PBIA fibers. Herein, carbon nanotubes (CNTs) are selected as an orientation seed. Their structural features allow CNTs to orient during the spinning process, which can induce an orderly arrangement of polymers and improve the orientation of the fiber microstructure, including in the crystalline and amorphous regions. To ensure the complete one‐dimensional topology of long CNTs (∼10 μm), PBIA is used as an efficient dispersant to overcome dispersion challenges. The p‐CNT/PBIA fibers (10 μm‐SWNT 0.025 wt%) exhibit an increase of 22% in tensile strength and 23% in elongation, with a maximum tensile strength of 7.01±0.31 GPa and a reinforcement efficiency of 893.6. The artificial muscle fabricated using CNT/PBIA fibers exhibits a 34.8% contraction and a 25% lifting of a 2 kg dumbbell, providing a promising paradigm for high‐performance organic fibers as high‐load smart actuators.This article is protected by copyright. All rights reserved

Fabricating Ultrastrong Carbon Nanotube Fibers via a Microwave Welding Interface

“…In the wet spinning process, the infiltration of PBIA can effectively facilitate intertube load transfer and enhance tensile strength (Figure 2d and Figure S8, Supporting Information). This enhancement is attributed to the noncovalent π−π interactions between CNT and PBIA, 44 even though there is a slight reduction in the orientation degree, decreasing from 0.94 to 0.92. The tensile modulus of PCNTF (255.15 ± 14.12 GPa) is higher than that of CNTF (206.21 ± 14.41 GPa).…”

Perception-Actuation Integrated Artificial Muscle Fibers: From Structural Design to Applications

“…Artificial muscle fibers that provide large linear contractile strokes and high mechanical energy output are of great interest because of their potential applications in some smart structures and systems. − Materials for lightweight and flexible artificial muscle fibers are abundant, including but not limited to synthetic polymers, − natural polymers, − carbon nanomaterials, − and nickel–titanium alloys. − Artificial muscle fibers prepared from these materials in response to stimulation can generate a >50% reversible contractile stroke and a >2 J g –1 work capacity, − which are larger than the ∼20% contractile stroke and 0.04 J g –1 work capacity achieved by natural skeletal muscle . The development vision of artificial muscle fibers is not only to surpass natural muscle in terms of actuation performance but also to reproduce more similar functionalities of natural muscle, which is essential for their real-world application in some advanced and precise devices.…”