Chen Jiali, Chen Xuezhe, Su Yaozhuo, Shen Bin, Zheng Wenge
Ningbo Key Lab of Polymer Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang province, 315201, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Mater Horiz. 2024 Dec 9;11(24):6381-6390. doi: 10.1039/d4mh00774c.
The increasing miniaturization and intelligence of flexible electronic devices pose a challenge to the facile and scalable fabrication of multifunctional stretchable electromagnetic interference (EMI) shielding films with strain-stable shielding effectiveness (SE). This paper presents a highly stretchable liquid metal/thermoplastic polyurethane (LM/TPU) composite film produced a facile method of scraping and pre-stretching induced activation. The TPU matrix endows the activated LM/TPU (ALMT) film with excellent tensile properties (elongation at break >700%), and the stable and malleable three-dimensional conductive LM network enables the ALMT film to exhibit almost negligible resistance changes and strain-enhanced conductivity during stretching, resulting in excellent strain-insensitive far-field and near-field shielding capabilities. Moreover, the high EMI SE up to ∼60 dB in the tensile state (0-400%) and reduced thickness from ∼75 to ∼50 μm during stretching allow the SE/thickness values of the ALMT film to increase from ∼700 to ∼1200 dB mm, outperforming most of the reported LM/polymer composites. Furthermore, the stretchability of the ALMT film provides efficient Joule-heating performance even under substantial deformation, and it can also serve as a strain sensor for real-time monitoring of human motion. The strain-insensitive EMI shielding behavior as well as the outstanding Joule heating and sensing performance of the ALMT film renders it a promising candidate for next-generation flexible electronic devices.
柔性电子设备日益小型化和智能化，这对具有应变稳定屏蔽效能（SE）的多功能可拉伸电磁干扰（EMI）屏蔽膜的简便且可扩展制造提出了挑战。本文介绍了一种通过刮涂和预拉伸诱导活化的简便方法制备的高可拉伸液态金属/热塑性聚氨酯（LM/TPU）复合膜。TPU基体赋予活化的LM/TPU（ALMT）膜优异的拉伸性能（断裂伸长率>700%），稳定且可延展的三维导电LM网络使ALMT膜在拉伸过程中电阻变化几乎可忽略不计，并具有应变增强的导电性，从而具备优异的应变不敏感远场和近场屏蔽能力。此外，在拉伸状态（0-400%）下高达约60 dB的高EMI SE以及拉伸过程中厚度从约75μm减小到约50μm，使得ALMT膜的SE/厚度值从约700 dB mm增加到约1200 dB mm，优于大多数已报道的LM/聚合物复合材料。此外，ALMT膜的可拉伸性即使在大幅变形下也能提供高效的焦耳热性能，并且它还可以用作实时监测人体运动的应变传感器。ALMT膜的应变不敏感EMI屏蔽行为以及出色的焦耳热和传感性能使其成为下一代柔性电子设备的有前途的候选材料。
