Li Ying, Li Yudi, Zhao Linlin, Feng Wei, Chen Siyu, Guo Siren, Yang Xulin, Wang Pan, Li Kui, Taieh Nabil Kadhim, Cerullo Giulio, Wei Hanjun
School of Mechanical Engineering, Chengdu University, 2025 Chengluo Avenue, Chengdu 610106, China.
Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano 20133, Italy.
ACS Appl Mater Interfaces. 2025 May 7;17(18):27178-27187. doi: 10.1021/acsami.5c03124. Epub 2025 Apr 25.
Smart microwave absorption (MA) materials that respond to environmental stimuli are highly sought after for advanced electromagnetic interference protection, particularly those with superior mechanical properties. In this study, we present a temperature-responsive composite material composed of poly(-isopropylacrylamide) (PNIPAAm) and a polyurethane (PU) sponge loaded with graphene oxide (PU@GO), referred to as PGPC. This composite exhibits switchable MA behavior below and above its lower critical solution temperature (LCST). Below LCST at 20 °C, the material shows minimal MA effectiveness (reflection loss < -10 dB), while at 50 °C, the reflection loss significantly improves to -42 dB with a bandwidth of 3.45 GHz. Structural characterization, both in situ and ex situ, reveals that this tunable behavior is driven by the reversible dissociation and reconstruction of a three-dimensional (3D) graphene network, triggered by the thermally induced movement of PNIPAAm molecular chains grafted onto the graphene sheets. Furthermore, the incorporation of PU enhances the composite's mechanical properties. The ability of PGPC to combine switchable MA performance with mechanical robustness makes it a promising candidate for intelligent, adaptive electromagnetic interference protection material, addressing current technological needs in dynamic environments.
能够响应环境刺激的智能微波吸收（MA）材料在先进电磁干扰防护领域备受青睐，尤其是那些具有卓越机械性能的材料。在本研究中，我们展示了一种由聚（N-异丙基丙烯酰胺）（PNIPAAm）和负载氧化石墨烯的聚氨酯（PU）海绵组成的温度响应复合材料（PU@GO），称为PGPC。该复合材料在其低临界溶液温度（LCST）上下表现出可切换的MA行为。在20°C低于LCST时，材料显示出最小的MA效果（反射损耗<-10 dB），而在50°C时，反射损耗显著提高到-42 dB，带宽为3.45 GHz。原位和非原位的结构表征表明，这种可调行为是由接枝在石墨烯片上的PNIPAAm分子链的热诱导运动触发的三维（3D）石墨烯网络的可逆解离和重构驱动的。此外，PU的加入增强了复合材料的机械性能。PGPC将可切换的MA性能与机械稳健性相结合的能力使其成为智能、自适应电磁干扰防护材料的有前途的候选者，满足了动态环境中的当前技术需求。
