共价插层MXene/石墨烯复合薄膜可极端条件下实现超灵敏声学传感器

摘要：开发高灵敏度且能在极端环境下运行的传感器，对特定智能技术的发展具有重要意义。具有高导电性的大尺寸MXene层已被广泛用于组装高性能传感薄膜。然而，重叠的大尺寸MXene层之间的间隙会降低机械性能，并加速层状结构在空气/水环境中的氧化。本文，中国石油大学（华东）

1成果简介

开发高灵敏度且能在极端环境下运行的传感器，对特定智能技术的发展具有重要意义。具有高导电性的大尺寸MXene层已被广泛用于组装高性能传感薄膜。然而，重叠的大尺寸MXene层之间的间隙会降低机械性能，并加速层状结构在空气/水环境中的氧化。本文，中国石油大学（华东）韩俊伟副教授、智林杰教授等在《Carbon》期刊发表名为“Covalently intercalated MXene/graphene composite film enables ultrasensitive acoustic sensors under extreme conditions”的论文，研究提出一种基于共价插层MXene复合传感薄膜，通过微米级石墨烯层与大尺寸MXene层共价连接，再经环氧丙基三甲氧基硅烷（PGPTMS）交联处理，实现高抗拉强度与空气/水分渗透抑制。由此制备的强韧抗氧化传感材料，即使在极端条件（200℃和100%相对湿度）下，仍能以1728 kPa−1的高灵敏度识别特征微弱声信号（

2图文导读

图1. Interlayer bondings in the MXene/rGO-PGPTMS film. (a) Schematic of chemically interfacial bridging in MXene/rGO-PGPTMS film. (b) Photograph of a folded MXene/rGO-PGPTMS film. (c) AFM image of GO intercalated MXene flake. (d) Cross-sectional SEM image of the MXene/rGO-PGPTMS film and (e) the corresponding elemental mapping of Ti, Si, C, and O. (f) UV-vis absorption spectra of MXene, GO, and MXene/GO films. (g) XRD patterns. (h) XPS of C 1s spectra. (i) XPS of Ti 2p spectra, proving the formation of Ti-O-C and Ti-O-Si covalent bonding.

图2. Mechanical properties and oxidation resistance characterizations of MXene/rGO-PTMS film. (a) Typical tensile stress-strain curves for the MXene/GO composite film with different GO proportions. (b) Typical tensile stress-strain curves for the investigated MXene/rGO-PGPTMS film. (c) TGA and DSC curves of pure MXene, MXene/rGO-PGPTMS films are tested in the air atmosphere using a heating rate of 10 K min-1. (d) Localized magnification of TGA curve before 160oC. Electrical conductance retention percentages as a function of time for MXene and MXene/rGO-PGPTMS films under conditions of (e) 15 days' storage in humid air with 100% relative humidity and (f) 18 hours' storage in a high temperature and humidity environment of 200oC with 100% relative humidity. Raman spectra of (g) MXene and (h) MXene/rGO-PGPTMS film before and after treatment under air at 200oC with 100% relative humidity for 0, 10, 20, and 30 h. (i) IR photographs of MXene and MXene/rGO-PGPTMS films on a hot plate with a constant temperature of 100oC and 200oC.

图3. Pressure sensing test using the MXene/rGO-PGPTMS film sound detector. (a) Schematic pressure-sensing models of the MXene/rGO-PGPTMS film during acoustic vibration. (b) Sensitivity curve of the MXene/rGO-PGPTMS film sensor. (c) Frequency response curve. (d) 100 and 101 Hz frequency differentiation. (e) Frequency I-T curve. (f) Response/recovery time curve. (g) Minimum pressure detection limit. (h) Stability performance during 500 acoustic vibration cycles at 200 Hz.

图4. Soundscape and physiological detection and discrimination by the MXene/rGO-PTPMS film sound detector. (a) Schematic of the experimental appliance for sound signal sensing. (b) Waveform of Chinese "ni" "ni hǎo" read by four times and comparison of two waveforms of "ni". (c) Recognition of English words and Chinese characters. (d) Discrimination of animal sound recordings. (e) Recognition of tone. (f) Recognition of sound loudness. (g) Recognition of the sound speed. (h) Comparison of the speech signal waveforms of Chinese sentences in quiet and noisy environments collected. (i) Six volunteer timbre recognition. (j) Pressing, blowing, tapping, pulsing sound recognition.

图5. Operation of MXene/rGO-PGPTMS film sound detector under extreme conditions. (a) Acoustic test in high humidity and high heat environment (200oC, 100% relative humidity). (b) Frequency response curve. (c) Frequency differentiation. (d) sensitivity curve of the MXene/rGO-PGPTMS film sensor. (e) Cycling performance.

3小结

本文提出一种共价插层策略，用于构建高性能的MXene基复合薄膜传感器。该MXene基复合薄膜的关键制备策略在于：

1）通过掺入微小石墨烯片层并利用Ti-O-C键实现层间共价桥接，有效消除MXene片层间空隙；

2）借助PGPTMS形成的Ti-O-Si键增强界面相互作用；

3）同时保持高片层取向度。所得薄膜在力学性能和抗氧化性能方面均显著提升。

作者采用导电MXene复合薄膜进行声学传感，结果表明该传感薄膜具有高灵敏度、低检测限和宽频谱响应特性。在语音交互与健康检测中，该传感装置在识别语音及生理信号方面表现优异。同时，该传感装置在极端高温高湿环境下的声学检测性能同样出色。本研究通过缩小层间间隙、增强层间相互作用来提升薄膜传感器的机械性能与抗氧化性能，为探索极端工况下高灵敏度柔性薄膜提供了关键设计启示。

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