Song Shaokang, Zhang Zhen, Hao Mingyu, Liu Ya, Zhang Xin, Ma Leyuan, Zhang Zhenxiu
Ministry of Education/Shandong Provincial Key Laboratory of Rubber-Plastics, Qingdao University of Science and Technology, Qingdao, Shandong Province 266042, PR China.
College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao, Shandong Province 266061, PR China.
J Colloid Interface Sci. 2025 Jul 25;700(Pt 3):138536. doi: 10.1016/j.jcis.2025.138536.
The growing prevalence of electromagnetic technologies has highlighted the critical need for adaptive shielding materials in modern communication systems. However, traditional composites are unable to cope with the dynamic electromagnetic environments found in critical applications such as aerospace and wearable technology. This study used supercritical CO₂ technology to prepare lightweight flexible electromagnetic interference (EMI) shielding foams with shape memory (SM) function, which achieved dynamic regulation of EMI shielding effectiveness (SE) through self-fixed deformation behavior. By constructing carbon nanotube (CNT)-graphene hierarchical conductive network, a 12 order of magnitude leap in conductivity was achieved at only 3 wt% of ultralow filler loading. Incorporating carbon fiber cloth (CFC) as an interlayer enhanced both shape fixation and recovery rates to 99.99 %, while boosting specific EMI SE to 1060.43 dB·cm/g. The material achieves absorption-led electromagnetic wave dissipation through a unique "absorption-reflection-absorption" synergistic mechanism, which greatly reduces secondary electromagnetic wave pollution, and exhibits 79 % wide-area EMI SE tunability (48.78-10.11 dB) through shape memory actuation. In addition, this mechanically adaptive foam maintains excellent durability in 40 cycles of SM testing and 100 cycles of heat cycle testing. Practical application was verified through an adaptive smart conference system capable of shape-mediated signal switching for secure information control. This work demonstrates how dynamic responsiveness, excellent shielding performance, and reliable operational stability can be achieved simultaneously, with important implications for 5G communications, aerospace, and next-generation electronic systems.
电磁技术的日益普及凸显了现代通信系统中对自适应屏蔽材料的迫切需求。然而，传统复合材料无法应对航空航天和可穿戴技术等关键应用中存在的动态电磁环境。本研究采用超临界二氧化碳技术制备了具有形状记忆（SM）功能的轻质柔性电磁干扰（EMI）屏蔽泡沫材料，该材料通过自固定变形行为实现了EMI屏蔽效能（SE）的动态调节。通过构建碳纳米管（CNT）-石墨烯分级导电网络，仅在3 wt%的超低填料负载量下就实现了电导率12个数量级的跃升。引入碳纤维布（CFC）作为中间层，将形状固定率和回复率均提高到99.99%，同时将比EMI SE提高到1060.43 dB·cm/g。该材料通过独特的“吸收-反射-吸收”协同机制实现了以吸收为主导的电磁波耗散，大大减少了二次电磁波污染，并通过形状记忆驱动展现出79%的大面积EMI SE可调性（48.78 - 10.11 dB）。此外，这种机械自适应泡沫在40次SM测试循环和100次热循环测试中保持了优异的耐久性。通过一个能够进行形状介导信号切换以实现安全信息控制的自适应智能会议系统验证了其实际应用。这项工作展示了如何同时实现动态响应性、优异的屏蔽性能和可靠的运行稳定性，对5G通信、航空航天和下一代电子系统具有重要意义。
