Advanced Materials Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China.
State Key Laboratory of Pharmaceutical Biotechnology, Division of Sports Medicine and Adult Reconstructive Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, 210008, China.
Small. 2024 Nov;20(48):e2405277. doi: 10.1002/smll.202405277. Epub 2024 Aug 27.
Coiled artificial muscle yarns outperform their straight counterparts in contractile strokes. However, challenges persist in the fabrication complexity and the susceptibility of the coiled yarns to becoming stuck by surrounding objects during contraction and recovery. Additionally, torsional stability remains a concern. In this study, it is reported that straight carbon nanotube (CNT) yarns when driven by a low-voltage electrochemical approach, can achieve a contractile stroke that surpasses even NiTi shape memory alloy fibers. The key lies in the suitable match between a yarn consisting of randomly aligned CNTs and the reversible and substantial electrochemical swelling induced by solvated ions. Wrinkled structures are formed on the surface of the CNT yarn to adapt to the swelling process. This not only assures torsional stability but also enhances the surface area for improved electrode-electrolyte interaction during electrochemical actuation. Remarkably, the CNT artificial muscle yarn generates a contractile stroke of 8.8% and an isometric stress of 7.5 MPa under 2.5 V actuation voltages, demonstrating its potential for applications requiring low energy consumption while maintaining high operational efficiency. This study highlights the crucial impact of CNT orientation on the effectiveness of electrochemically-driven artificial muscles, signaling new possibilities in smart material and biomechanical system development.
螺旋状人工肌肉纱线在收缩运动中的表现优于其直状对应物。然而，在制造复杂性以及螺旋纱线在收缩和恢复过程中容易被周围物体卡住的问题上仍然存在挑战。此外，扭转稳定性仍然是一个关注点。在这项研究中，据报道，当受到低电压电化学驱动时，直状碳纳米管（CNT）纱线可以实现超过镍钛形状记忆合金纤维的收缩运动。关键在于由随机排列的 CNT 组成的纱线与溶剂化离子引起的可逆和实质性电化学膨胀之间的合适匹配。在 CNT 纱线的表面形成褶皱结构以适应膨胀过程。这不仅确保了扭转稳定性，还增加了表面积，以改善电化学驱动过程中的电极-电解质相互作用。值得注意的是，在 2.5 V 驱动电压下，CNT 人工肌肉纱线产生了 8.8%的收缩运动和 7.5 MPa 的等长应力，表明其在需要低能耗的应用中具有潜力，同时保持了高运行效率。这项研究强调了 CNT 取向对电化学驱动人工肌肉的有效性的关键影响，为智能材料和生物力学系统的发展带来了新的可能性。
