基于纖維素的空氣凝膠因其互聯多孔網絡、低密度和優異的壓縮性，特別適合用于柔性傳感器，這些特性使得有效的變形檢測和信號傳輸成為可能。然而，纖維素氣凝膠在應變傳感應用中的廣泛采用受到其有限壓縮性和抗疲勞性的限制。為解決這些問題，本文，浙江科技大學蔡海鶯副教授、浙江省林業科學研究院王進、江蘇省新型環保重點實驗室韓申杰等研究人員在《ACS Appl. Electron. Mater》期刊發表名為“Synergistically Reinforced Bamboo Cellulose–Graphene Aerogel Sensors with Highly Elasticity and Strain Sensitivity”的論文，研究通過協同方法開發了復合氣凝膠傳感器，該方法將通過TEMPO氧化法制備的竹纖維素納米纖維（BCNFs）與甲基三甲氧基硅烷（MTMS）改性及氧化石墨烯（GO）摻雜相結合。

所得的BCNF/MTMS/還原石墨烯氧化物（rGO）氣凝膠通過凍干和碳化的一體化工藝制備。所制備的壓阻式傳感器具有彈性、導電的多孔結構，具備卓越的傳感性能，展現出高壓縮敏感度（在20–30%應變下，應變系數可達2.45）。此外，該傳感器在監測人體關節運動方面表現出優異性能，展現出作為下一代健康監測應用中高性能柔性可穿戴應變傳感器的潛力。本研究為開發具有增強機械和傳感性能的先進纖維素基氣凝膠傳感器提供了可行策略。

圖文導讀

圖1. Preparation process diagram of BCNF/MTMS/rGO aerogels.

圖2. SEM images of BCNF/MTMS/GO-0.5 (A, D), BCNF/MTMS/GO-1 (B, E), BCNF/MTMS/GO-1.5 (C, F), BCNF/MTMS/rGO-0.5 (G, J), BCNF/MTMS/rGO-1 (H, K), and BCNF/MTMS/rGO-1.5 (I, L) aerogels.

圖3. (A) TEM image of BCNF. (B) FTIR spectra and (C) XRD spectra of BF, PBF, BCNF, BCNF/MTMS/GO-1 aerogel, and BCNF/MTMS/rGO-1 aerogel. (D) XPS spectra of BCNF, BCNF/MTMS/GO-1 aerogel, and BCNF/MTMS/rGO-1 aerogel, along with (E) C 1s and (F) Si 2p spectra of BCNF/MTMS/rGO-1 aerogel. (G) Nitrogen adsorption–desorption isotherms and (H) pore sizes of BCNF, BCNF/MTMS/GO-1 aerogel, and BCNF/MTMS/rGO-1 aerogel.

圖4. (A) Loading and unloading processes of BCNF/MTMS/rGO-1 aerogel. (B) Retention of maximum stresses in BCNF/MTMS/GO-0.5, BCNF/MTMS/GO-1, and BCNF/MTMS/GO-1.5 aerogels at a strain of 50% for 50 cycles. (C) Stress–strain curves of BCNF/MTMS/rGO-1 aerogel at the maximum strains of 10, 30, and 50%, respectively. (D) Fatigue tests of several selected cycles on BCNF/MTMS/rGO-1 aerogel at 50% strain. (E) Retentions of maximum stress and total strain loss of BCNF/MTMS/rGO-1 aerogel during 100 cycles at 50% strain. (F) Comparison of water contact angles for BCNF, BCNF/MTMS/GO-1, and BCNF/MTMS/rGO-1 aerogels.

圖5. Electromechanical performance of BCNF/MTMS/rGO-1 aerogels. (A) Mechanism of electrical resistance variation. (B) Current–voltage characteristics under different strains (0, 10, 20, 30, 40, and 50%). Variation of resistance with different applied strains (C) and frequencies (D). (E) Strain-sensing performance of BCNF/MTMS/rGO-1 aerogel. (F) Cycling stability test under 30% strain for 800 cycles.

圖6. (A) Schematic representation of the pressure sensor’s structure. (B) Different bending angle signals of the finger. Resistance variation curves during the processes of (C) finger bending, (D) knee bending, and (E) elbow bending.

小結

本研究通過優化溶液混合和凍干工藝，成功制備了BCNF/MTMS/rGO-1氣凝膠。竹纖維素納米纖維（BCNF）、甲基三甲氧基硅烷（MTMS）與還原石墨烯氧化物（rGO）的協同組合，制備出具有堅固三維多孔結構的氣凝膠，該結構賦予其機械韌性，同時集成導電網絡可實現敏感應變響應（GF在20–30%應變下可達2.45），并展現出卓越的循環穩定性 （壓縮循環穩定性可達800次循環）。基于氣凝膠的傳感器在監測復雜人體運動方面表現出色，包括精細的手指運動和大范圍的關節彎曲。這些結果表明，BCNF/MTMS/rGO-1氣凝膠在毫米級運動（如手指、肘部和膝蓋彎曲）中展現出卓越的機械韌性和可靠的壓阻響應，使其成為針對這些關節級變形可穿戴設備的理想候選材料。

文獻：

https://doi.org/10.1021/acsaelm.5c01129

信息來源：材料分析與應用