Xin Yumeng, Lan Jingyun, Xu Jun, Wu Dongfang, Zhang Jiuyang
School of Chemistry and Chemical Engineering and Jiangsu Hi-Tech Key Laboratory for Biomedical Research, Southeast University, Nanjing 211189, People's Republic of China.
Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, Minneapolis, Minnesota 55414, United States.
ACS Appl Mater Interfaces. 2021 Apr 28;13(16):19351-19359. doi: 10.1021/acsami.1c03375. Epub 2021 Apr 14.
Flexible electronic devices have penetrated into a variety of industry sectors (i.e., consumer electronics, automotive, and medical) in human life, and this calls for better properties of stretchable conductive composites as the crucial elements. Traditionally, conductive inorganic fillers are incorporated in flexible polymers to prepare conductive composites, which falls short of the required properties in more demanding devices nowadays due to limited deformation, low conductivity, and poor processability. Herein, liquid metals were successfully incorporated in microporous polymer matrixes using a simple codissolving and film casting/solvent evaporation approach. The microporous liquid metal-embedded polymer (LMEP) was insulative as fabricated due to discontinuous liquid metals (LMs), while it became conductive upon stretching. Interestingly, the LMEP films showed a reversible insulator-conductor transition due to the regenerated pores in polymer matrix under organic vapor. Negligible changes in the resistance value were seen even after 50 solvent exposure-tensile strain cycles, demonstrating the excellent stability of the electrical properties of these films. Furthermore, most of the commercially available soluble polymers including rigid plastics and soft elastomers are suitable for the fabrication of LMEP. With the ideal characteristics, they have been successfully exploited in model alarm systems to prevent temperature overloads and solvent leakage, showcasing the great potential in next generation sensors used in industry settings.
柔性电子设备已渗透到人类生活中的各种行业领域（即消费电子、汽车和医疗），这就要求作为关键元件的可拉伸导电复合材料具有更好的性能。传统上，将导电无机填料掺入柔性聚合物中来制备导电复合材料，由于其变形受限、导电性低和加工性差，如今在要求更高的设备中无法满足所需性能。在此，通过简单的共溶解和流延/溶剂蒸发方法，成功地将液态金属掺入微孔聚合物基体中。由于液态金属不连续，制备出的微孔液态金属嵌入聚合物（LMEP）在初始状态下是绝缘的，而在拉伸时变为导电。有趣的是，由于有机蒸汽作用下聚合物基体中再生的孔隙，LMEP薄膜呈现出可逆的绝缘体 - 导体转变。即使经过50次溶剂暴露 - 拉伸应变循环后，电阻值的变化也可忽略不计，表明这些薄膜的电学性能具有优异的稳定性。此外，大多数市售的可溶性聚合物，包括刚性塑料和软质弹性体，都适用于LMEP的制备。凭借这些理想特性，它们已成功应用于模型报警系统中，以防止温度过载和溶剂泄漏，展示了在工业环境中下一代传感器的巨大潜力。
