Growing interests have been received for conductive fibers due to their electrical conductivity with one-dimensional structures. Fibers with liquid metal (LM) as a conductive filler exhibit distinctive advantages, such as metallic conductivity and superior stretchability. So far, the unique characteristics of LM have not been fully used in one-dimensional materials. This work successfully created conductive fibers with an LM filler gradient dispersed in a polymer matrix. These LM fibers showed distinguished thermally programmable shapes and electrical conductivities. The fibers can be programed into straight, bent or helical shapes with controlled bending degree depending on the heat absorbed by the LM inside the fiber. Interestingly, the resistance of the LM fibers could also be tuned by the thermal energy. Upon heating, the LM fibers showed a transition from an insulator (10⁸ Ω) to a conductor (10 Ω) with programmed conductivity along the axial direction. More importantly, both the shape programmability and conductivity transition were highly reversible by heating and cooling. The programmed helical LM fibers successfully mimicked natural plant tendrils with excellent mechanical performance and acted as smart strain-mediated conductors. The LM fibers could also be applied as flexible temperature electrical switches in high-tech devices, such as lunar rovers.

中文翻译：

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具有可逆热可编程性的液态金属梯度纤维

由于导电纤维具有一维结构的导电性，因此越来越引起人们的兴趣。以液态金属（LM）作为导电填料的纤维具有独特的优势，例如金属导电性和出色的拉伸性。到目前为止，LM的独特特性尚未在一维材料中得到充分利用。这项工作成功地创建了具有LM填料梯度分散在聚合物基质中的导电纤维。这些LM纤维显示出杰出的热可编程形状和电导率。可以根据纤维内部LM吸收的热量将纤维编程为具有受控弯曲度的直线，弯曲或螺旋形形状。有趣的是，LM纤维的电阻也可以通过热能来调节。加热后⁸ Ω）到导体（10Ω）与沿轴向编程导电性。更重要的是，通过加热和冷却，形状可编程性和电导率转变都是高度可逆的。程序设计的螺旋LM纤维成功地模仿了具有出色机械性能的天然植物卷须，并充当了聪明的应变介导导体。LM纤维还可以用作诸如月球漫游车之类的高科技设备中的柔性温度电气开关。