基于硝化纳米纤维素/琼脂的高灵敏度湿度传感器

湿敏材料是决定湿度传感器性能的关键，本研究将具有特殊化学结构的纤维素和琼脂这两种生物质材料有机结合起来，制备具有不同湿度敏感性的硝化纳米纤维素/琼脂（nitrocellulose nanocrystals/Agar，NCNCs/Agar）复合敏感膜材料，基于石英晶体微天平（quartz crystal microbalance，QCM）制备出具有高灵敏度的湿度传感器。结果表明，NCNCs/Agar复合敏感膜修饰的QCM湿度传感器的灵敏度和频率响应值较单一材料敏感膜修饰的QCM均有较明显的提高。经过优化测试，得到NCNCs与琼脂的最佳质量比为1∶25，涂覆2.049μg敏感材料的QCM传感器（QCM-b）性能最优异。在相对湿度（RH）11%~84%下，QCM-b具有良好的线性（R²=0.9933），灵敏度为32.54Hz/%RH。在RH 11%~97%下，QCM-b响应值可达到-5820Hz，具有优异的对数拟合系数（R²=0.9994），恢复时间短（5s），并且具有良好的重现性和长期稳定性，显示出在湿度探测领域的良好应用前景。

A highly sensitivity humidity sensor based on nitrocellulose nanocrystals/agar

Humidity sensitive materials are crucial for the humidity sensors. In this study, a novel idea of combing two biomass products with unique chemical structures, cellulose and agar, to prepare nitrocellulose nanocrystals/agar (NCNCs/Agar) composite sensitive film materials with different humidity sensitivity was presented. Based on the above-mentioned sensitive film materials, a high sensitivity quartz crystal microbalance (QCM) humidity sensor was developed. The results revealed that the sensitivity and frequency response of the NCNCs/Agar-based QCM humidity sensor were significantly higher than those of the sensor based on a single-component sensitive film. The results confirmed that the humidity sensor with NCNCs/Agar (optimum NCNCs to agar mass ratio of 1∶25) loading of 2.049μg (QCM-b) exhibited the excellent performance. In addition, the sensor showed excellent linearity (R² =0.9933) in 11%—84% relative humidity (RH) and high sensitivity (32.54Hz/%RH). In 11%—97% RH, the humidity sensor showed high response value (-5820Hz), excellent logarithmic linearity (R² =0.9994), short recovery time (5s), good reproducibility and long-term stability. In conclusion, these results indicated that the NCNCs/Agar-based QCM sensor demonstrated great promise for practical use in humidity detection.