高产率石墨烯/纤维素导电复合水凝胶，用于运动检测、医疗诊断等

摘要：石墨烯因其卓越的导电性和超强的机械强度而被广泛认为是导电水凝胶的有效填充物，这对于开发先进的可穿戴应变传感器至关重要。然而，追求高效、环保的石墨烯剥离策略仍然是一项艰巨的挑战。本文，华南理工大学Qing Li、佛山大学胡德超等研究人员在《ACS Appl.

1成果简介

石墨烯因其卓越的导电性和超强的机械强度而被广泛认为是导电水凝胶的有效填充物，这对于开发先进的可穿戴应变传感器至关重要。然而，追求高效、环保的石墨烯剥离策略仍然是一项艰巨的挑战。本文，华南理工大学Qing Li、佛山大学胡德超等研究人员在《ACS Appl. Polym. Mater》期刊发表名为“High-Yield Graphene/Cellulose Nanocrystal Hybrid Material for Robust and Conductive Composite Hydrogels with Tunable Strain Sensing Capability”的论文，研究提出了一种结合NaHCO3预处理和纤维素纳米晶（CNC）辅助液相剥离的新型石墨烯高产制备方法。

研究发现，经过三轮预处理后，石墨的剥离产率是未处理石墨的2.2倍，达到31%。此外，与未加入CNC的石墨烯相比，加入CNC的石墨烯剥离率提高了 4.6 倍。由此产生的石墨烯/CNC（LEG/C）混合材料随后作为填充物被整合到聚丙烯酰胺（PAM）水凝胶中，产生了一种具有超高拉伸性能（最大断裂伸长率为 3000%）和优异传感性能（在 300% 应变时灵敏度系数 GF = 2.7，同时在 5% 应变时保持高灵敏度）的复合水凝胶。这项研究提出了一种几乎无污染且经济高效的石墨烯剥离方法，并开发出一种具有可调应变传感能力的坚固导电复合水凝胶，为先进的可穿戴电子产品领域带来了巨大的发展前景。

2图文导读

图1. (a) Schematic diagram of graphene exfoliation, (b) preparation of the composite hydrogel, and (c) the composite hydrogel used as a strain sensor.

图2. (a) XRD patterns of graphite pretreated with a different number of cycles; (b) TGA curves of LEG/C hybrid materials prepared with different treatment times and (c) their components and exfoliation yield; (e) TGA curves of LEG/C hybrid materials prepared with different proportion of CNC addition and (f) their components and exfoliation yield; SEM images of (d) untreated industrial graphite, (g) 3-G and (h) 3-LEG/C-1; (i) AFM image with height analysis of 3-LEG/C-1; (j) Raman spectroscopy of industrial graphite and hybrid material; (k) XRD patterns of CNC, industrial graphite and 3-LEG/C-1; and (l) Scatter plots of 3-LEG/C-1 before and after 1 month of storage.

图3. (a) Photographs of the strain ability of the LEG/C-PAM composite hydrogel; (b) stress–strain curves and (c) electrical conductivity of composite hydrogels with 0.5 wt % different LEG/C hybrid materials; (d) stress–strain curves and (e) electrical conductivity of the composite hydrogels with different addition amounts of 3-LEG/C-1 hybrid material. (f) Stress–strain curves of the LEG/C-PAM hydrogel with different cycles of cyclic stretching test at 50% strain.

图4. (a) Variation in the brightness of a small bulb in response to different elongations of the hydrogel; (b) schematic diagram of hydrogel sensing performance test; (c) changes of resistance and bulb in the process of cutting, healing, and cutting of hydrogel; (d) schematic diagram of the change rate of hydrogel resistance under rapid stretching and unloading; (e) resistance change rate at 100% strain under different tensile rates; resistance response of the composite hydrogel under (f) small strains and (g) large strains; (h) resistance response and GF of the composite hydrogel under different strains; and (i) hydrogel response curves during a 400 cyclic strain testing at a tensile unloading rate of 100 mm/min and strain of 50%.

图5. Hydrogel sensing curves when (a) different letters of “S, C, U, T” and (b) the word “hydrogel” was sounded; (c) the sensing curve of the hydrogel during cough; and schematic diagram of (d) finger joint, (e) wrist joint, and (f) elbow joint motion sensing.

3小结

综上所述，通过结合NaHCO3热膨胀预处理和纤维素纳米晶（CNC）辅助液相剥离，提出了一种高产率、低成本、环保的石墨烯制备策略。经过三轮预处理后，石墨的剥离产率比未经处理的石墨提高了 2.2 倍，达到 31%。此外，与未加入 CNC 的石墨烯相比，加入 CNC 的石墨烯剥离率提高了 4.6 倍。由此产生的石墨烯/CNC（LEG/C）混合材料随后成为柔性导电水凝胶的多功能填充物。CNC 表面丰富的羟基有助于与 PAM 基质形成大量分子间氢键，从而赋予复合水凝胶优异的拉伸性（3014%）、良好的导电性（280mS/m）和高应变灵敏度（GF>2.7）。基于复合水凝胶的应变传感器可用于发音和关节运动监测。上述令人鼓舞的结果表明，石墨烯/CNC混合材料的高产制备为构建具有可调应变传感能力的坚固导电复合水凝胶提供了创新机会，在智能可穿戴电子产品中大有可为。

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