Conductive composite materials with single-component active fillers often possess high filler content, poor mechanical performance, and unimproved sensing behaviors. To overcome these challenges, a flexible strain sensor with a sandwich structure was achieved by coupling one-dimensional conductive filler carbon nanotubes (CNTs) with two-dimensional MXene nanosheets on an aligned thermoplastic polyurethane (TPU) electrospinning fibrous film with wave structure through vacuum suction filtration and encapsulation with Ecoflex. The synergy of MXene and CNTs can be employed to develop a good conductive path in the matrix, which can realize versatile sensing performances. Meanwhile, the MXene-CNTs/TPU/Ecoflex composites (MCTEC) when stretched in vertical fiber direction exhibit low hysteresis owing to the combination of the aligned TPU fiber network with wave structure and the low viscoelasticity of Ecoflex. The strain sensor based on MCTEC also possesses a low detection limit (0.1% strain), wide sensing range (0-251% strain), fast response time (50 ms), and fine sensing recoverability. Additionally, this strain sensor can monitor human limb movement and vocalization, which facilitates the development of strain sensors in the field of intelligent healthcare.

中文翻译：

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基于定向热塑性聚氨酯纤维垫的高应变敏感和可拉伸多层导电复合材料，用于人体运动监测

具有单组分活性填料的导电复合材料通常具有高填料含量、差的机械性能和未改善的传感行为。为了克服这些挑战，通过真空抽吸将一维导电填料碳纳米管（CNT）与二维MXene纳米片耦合在具有波浪结构的排列热塑性聚氨酯（TPU）静电纺丝纤维膜上，实现了具有三明治结构的柔性应变传感器使用 Ecoflex 进行过滤和封装。MXene 和 CNT 的协同作用可用于在基体中形成良好的导电路径，从而实现多种传感性能。同时，由于排列的TPU纤维网络与波浪结构以及Ecoflex的低粘弹性相结合，MXene-CNTs/TPU/Ecoflex复合材料（MCTEC）在垂直纤维方向拉伸时表现出低滞后性。基于MCTEC的应变传感器还具有检测限低（0.1%应变）、宽传感范围（0-251%应变）、快速响应时间（50 ms）和良好的传感恢复能力。此外，该应变传感器还可以监测人体肢体运动和发声，有利于应变传感器在智能医疗领域的发展。