武汉理工大学《ACS AMI》：基于石墨烯组装薄膜的抗腐蚀、长通信距离RFID标签，用于地下无线温度传感

成果简介

土壤温度监测是现代农业生产体系的关键环节。然而，传统检测方式往往劳动密集、效率低，且对土壤埋设环境的适应性差。因此，开发可埋地、耐腐蚀且具备远距离无线传输能力的温度传感技术，对智慧农业与物联网感知具有重要意义。基于此，本文，武汉理工大学宋荣国 特设教授、祖浩然 特任教授等在《ACS Applied Materials & Interfaces》期刊发表名为”Anti-Corrosion and Long Communication Range RFID Tags Based on Graphene-Assembled Films for Underground Wireless Temperature Sensing”的论文，研究提出了一种基于无源射频识别（RFID）的石墨烯组装膜（GAF）温度传感系统。该工作以 GAF 制备天线与人工磁导体（AMC）结构，并集成商用 RFID 芯片实现温度检测，构建出兼具耐腐蚀与远距离通信能力的柔性传感标签。

此外，为进一步提升无线通信距离，研究专门设计并与传感器集成了一层 GAF 人工磁导体（AMC）。其低剖面高阻抗表面特性改善了标签的辐射方向图与读取效率，使系统的自由空间最大通信距离得到显著延伸。经测试，引入 GAF AMC 后，该 RFID 传感系统的最大自由空间通信距离由 10.1 m 提升至 16.8 m；在土壤环境中与标定水银温度计对比，GAF 温度传感器最大温度偏差为 1.2 °C、平均绝对误差为 0.366 °C。同时，该系统成功演示了实时无线数据采集与显示，使其适用于地下/土壤埋设温度监测场景。本研究提出了一种以石墨烯组装膜构建耐腐蚀、远距离 RFID 温度标签的设计策略，该策略有效克服了传统传感技术在埋地环境中的关键局限，为土壤温度无线监测提供了初步可行方案。

图文导读

Figure 1.Characterization of the graphene-assembled films. (a) Digital photo of large-scale GAF; (b) X-ray diffraction (XRD) pattern; (c) Raman spectrum of GAF; (d) Flexible display of GAF; and (e) surface and (f) cross-sectional SEM images of GAF.

Figure 2.Design and characterization of the proposed GAF RFID sensor: (a) GAF antenna layout; (b) digital photo of the fabricated GAF RFID sensor. Parametric variation of the antenna impedance with (c) length l₃; (d) width w₃ and (e) gap s. (f) Simulated and measured communication range performance of GAF RFID sensor: dashed line: simulated, solid line: measured (The illustration shows the testing equipment, the double-dotted dashed line marks the minimum read range across the entire UHF band (above 9.2 m)).

Figure 3.Corrosion resistance and temperature-sensing performance of the GAF RFID sensor. (a, b) Comparison of surface morphologies before and after 72 h of salt spray exposure for the (a) GAF and (b) copper foil. (c–e) Experimental setups for temperature measurement: (c) buried in soil, (d) placed in a flowerpot, and (e) on heating stage. (f–h) Corresponding temperature data comparisons between the proposed GAF RFID sensor and a reference mercury thermometer under the conditions in (c–e), respectively. Light pink shading indicates the range of deviation from the reference standard.

Figure 4.Performance enhancement of GAF RFID sensor through AMC integration. (a) Unit cell geometry of the proposed GAF AMC. (b) Digital photo of the fabricated 3 × 1 AMC array. (c) Schematic cross-section illustrating the integrated GAF sensor-AMC structure with a 20-mm-thick foam spacer. (d) Simulated gain comparison of the sensor with and without the AMC. (e) Measured communication range comparison of the sensor with and without the AMC.

Figure 5.Environmental robustness evaluation of the AMC-integrated sensor in soil. (a) Schematic illustration of the AMC-enhanced signal penetration mechanism. (b, c) Experimental photograph of a standalone sensor buried in shallow soil. (d, e) Experimental photographs of the standalone sensor buried at a depth of 20 cm, showing that the sensor becomes unreadable. (f, g) Experimental photographs of the integrated sensor-AMC system buried at the same depth of 20 cm, showing that reliable readout is maintained.

小结

综上所述，本文演示了一种耐腐蚀的UHF RFID温度传感系统，其中天线和AMC结构由石墨烯组装薄膜（GAF）制成，而温度传感功能则由市售的RFID芯片提供。该独立式GAF传感器在UHF频段下的最大通信距离为10.1米，集成AMC后进一步延长至16.8米，增幅达66%。在土壤埋设测试中，这种提升使得可靠读取的有效埋设深度从10厘米延长至20厘米。通过72小时盐雾测试验证了其优异的耐腐蚀性：在测试中，GAF样品保持完好，而铜箔对照样品则发生了严重腐蚀。高温传感精度已通过土壤埋设测试得到验证，与经校准的水银温度计相比，最大偏差为1.2 °C，平均绝对误差为0.366 °C。AMC结构显著增强了在土壤埋设环境（深度达20厘米）中的信号穿透能力，确保了在实际农业条件下可靠的无线通信，并成功演示了实时无线数据采集与显示功能。所提出的基于GAF的RFID传感系统为埋地温度监测提供了替代金属传感器的潜在可持续方案，并在精准农业和物联网相关领域展现出应用潜力。我们承认，加速腐蚀试验虽然有助于初步验证，但未能完全再现实际地下农业环境的复杂性，这些环境可能包括可变的pH值、肥料盐分、微生物活动、湿度波动以及机械应力。未来将系统地开展基于真实田间条件的长期埋土降解研究，以进一步验证所提议传感器的耐久性和可靠性。

文献：https://doi.org/10.1021/acsami.6c14140