Lizhong Dong,Ming Ren,Yulian Wang,Jian Qiao,Yulong Wu,Jianfeng He,Xulin Wei,Jiangtao Di,Qingwen Li
Artificial muscle fibers as a promising biomimetic actuator are needed for such applications as smart soft robots, muscle function restoration, and physical augmentation. Currently developed artificial muscle fibers have shown attractive performance in contractile and torsional actuations. However, the contractile muscle fibers do not have the capability of stimulus-responsive elongation, and real-time identifying their contractile position by themselves is still challenging. We report herein the preparation of a Ti3C2Tx MXene/single walled carbon-nanotubes (SWCNTs)-coated carbon nanotube (CNT)@polydimethylsiloxane (PDMS) coaxial muscle fiber that integrates the important features of self-position sensing and bi-lengthwise actuation. The bi-lengthwise actuation is realized by utilizing the large expansion coefficient difference of PDMS in response to solvent and heat, which results in ∼5% maximum elongation by n-heptane adsorption and ∼19% maximum contraction by electric heating under the optimal conditions. Meanwhile, due to the piezoresistive effect of the MXene/SWCNTs layer, the resistance change of this coating layer is almost linearly dependent on the contraction of the coaxial muscle fiber, providing a function of real-time self-position sensing. Furthermore, an application of using a bundle of these multifunctional coaxial muscle fibers for a bionic arm has been demonstrated, which provides new insights into the design of integrated intelligent artificial muscles with synergistic multiple functions.
Natural muscles feature resilient actuation, but currently developed artificial muscle fibers do not. The main challenge is serious plastic elongation, especially when artificial muscle fibers are operated at heavy loads, significantly limiting their applications. We report a resilient artificial muscle fiber that deploys an elastic sheath. The sheath enables full lengthwise recovery of the coiled artificial muscle fiber straightened at 375% strain. This muscle fiber produces natural muscle-like resilient actuation, which features elastic elongation when bearing heavy loads and consistent contractions at load-balanced muscle lengths. Two muscle fibers connected in an antagonistic structure, amounting to ∼8% of the weight of an electrical rudder system, efficiently control the flight attitude of a commercial ornithopter. An adaptive pressure band based on these muscle fibers provides rhythmic pressure to prevent venous diseases. Such resilient muscle fibers can offer important potential in robotics and wearable technologies that require high durability and adaptability.
危险品化学品经营许可证（带存储）