轻木基碳海绵/TPU复合压力传感器的制备与性能

刘玉慧; 柳仕林; 吴聪影; 何敬宗; 吴琪琳

轻木基碳海绵/TPU复合压力传感器的制备与性能

刘玉慧^{1, 2},
柳仕林^{1, 2},
吴聪影^{1, 2},
何敬宗^{1, 2},
吴琪琳^{1, 2, ,}

1.
东华大学纤维材料改性国家重点实验室, 上海 201620
2.
东华大学材料科学与工程学院, 上海 201620

基金项目: 国家自然科学基金重大项目(52090033/52090030)

详细信息

通讯作者:
吴琪琳，博士，教授，博士生导师，研究方向为高性能纤维及其复合材料，　E-mail：wql@dhu.edu.cn

中图分类号: TB33
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- 被引次数: 0
出版历程
- 收稿日期: 2022-10-28
- 修回日期: 2022-12-04
- 录用日期: 2023-01-09
- 网络出版日期: 2023-02-07

Preparation and performance of balsa wood-based carbon sponge /TPU composite pressure sensor

Yuhui LIU^{1, 2},
Shilin LIU^{1, 2},
Congying WU^{1, 2},
Jingzong HE^{1, 2},
Qilin WU^{1, 2
, ,}

1.
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620, China
2.
College of Materials Science and Engineering, Donghua University, Shanghai 201620, China

Funds: National Natural Science Foundation of China (No. 52090033/52090030)

摘要

摘要: 近年来，具有三维网状结构的柔性压力传感器展现出高度可逆压缩性和良好灵敏性等特点，其复杂的网络形态也有利于构建稳定的导电网络，在可穿戴电子设备、医疗诊断、人体健康监测等方面显示出巨大的应用前景。三维导电网络的构建和传感性能的优化成为目前柔性压力传感器的一个研究难点，因此本文针对柔性压力传感器的制备和性能提升进行了深入研究。本文以天然生物质材料轻木(Balsa Wood)为原材料，将纤维素酸性催化热解机理与轻木的碳化过程相结合，采用催化处理和多步碳化工艺，获得了高碳化得率(20.15%)的三维层状结构碳海绵(Carbonized Wood Sponge，CWS)，并通过TPU弹性体材料的浸渍，得到具有良好导电性和高度可逆压缩性的CWS/TPU复合传感层。将CWS/TPU复合材料作为导电传感元件，覆上电极后可制成柔性压力传感器。结果表明，该传感器压缩应变可达60%，在0-4 kPa压力范围内，其最高压力传感灵敏度(S)达12.87 kPa^-1，并且在超过5000次的压缩/释放周期后仍具有良好的传感稳定性，表现出良好的传感性能和环境稳定性。在实际应用方面，将其安装在人体的多个关节处，可以实时监测其运动状态，制备的传感器实现了对人体运动和生理信号的健康监测。1轻木基碳海绵/TPU复合压力传感器
- 碳海绵 /
- 催化碳化 /
- 三维导电网络 /
- 压力传感器 /
- 高灵敏度
Abstract: In recent years, flexible pressure sensors with three-dimensional mesh structure show high reversible compressibility and good sensitivity, and their complex network shape is also conducive to the construction of stable conductive network, which is widely used in human health monitoring, wearable devices, medical diagnosis and other fields. In this study, a carbonized wood sponge(CWS)/TPU composite pressure sensor with three-dimensional layered structure based on natural balsa wood was designed to construct a stable three-dimensional conductive network and optimize the sensing performance. The catalytic treatment, carbonization process, sensing performance and human applicability of the sensor were characterized. The results show that the carbon yield of the light wood-based CWS/TPU sensor by catalytic treatment and high temperature carbonization can reach 20.15%, the compressive strain can reach at 60%, and the maximum pressure sensing sensitivity (S) can reach 12.87 kPa⁻¹ in the pressure range of 0-4 kPa. Moreover, the sensor still has good sensing stability and environmental stability even after 5000 compression/release cycles, showing good sensing performance. The sensor was successfully used to monitor hand movement, walking and pulse in real time, which shows the potential application value of the sensor in motion and health monitoring.
- Carbon sponge /
- Catalytic carbonization /
- Three-dimensional conducting network /
- Pressure sensor /
- High sensitivity

HTML全文

图 1 碳海绵(CWS)/TPU柔性压力传感器的制备：(a)酸性催化CWS的制备过程；(b)碳化工艺图；(c)传感器结构示意图

Figure 1. Preparation of carbonized wood sponge(CWS)/TPU flexible pressure sensor: (a) Preparation process of acidic catalytic CWS; (b) Carbonization program; (c) Schematic diagram of the sensor structure

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图 2 化学处理和900℃碳化前后的形貌变化，天然轻木(a1~a3)，木海绵(WS)(b1~b3)，CWS的照片和SEM图(c1~c3)

Figure 2. Morphological changes before and after chemical treatment and carbonization at 900℃, photos and SEM images of natural balsa wood (a1~a3), Wood Sponge (WS) (b1~b3) and CWS(c1~c3)

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图 3 不同处理条件下的红外光谱图：(a)原木和WS；(b)催化处理前后的WS

Figure 3. FTIR spectra under different treatment conditions: (a) Nature wood and WS; (b) WS before and after catalytic treatment

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图 4 催化处理前后：(a)WS的TG和DTG曲线图；(b)不同碳化温度下CWS的碳化得率

Figure 4. Before and after catalytic treatment, (a) TG and DTG curves of WS; (b) Carbon yields of CWS at different carbonization temperatures

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图 5 不同碳化温度下CWS的拉曼光谱图：(a)直接碳化；(b)酸性催化后碳化

Figure 5. Raman spectra of CWS at different carbonization temperatures: (a) Directly carbonized; (b) Carbonized after acid catalysis

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图 6 CWS/TPU复合材料的力学性能：(a)CWS/TPU显示其高度可逆压缩性的示意图；(b)不同碳化温度下CWS/TPU在60%应变下的压缩应力-应变曲线图；(c)CWS/TPU在不同应变下的压缩应力-应变曲线图，插图为0-20%压缩范围内的放大图；(d)CWS/TPU在50%应变下循环5次下的压缩应力-应变曲线图

Figure 6. Mechanical properties of CWS/TPU composites: (a) Schematic diagram of CWS/TPU showing its highly reversible compressibility; (b) Compressive stress-strain curves of CWS/TPU under 60% strain at different carbonization temperatures; (c) Compressive stress-strain curves of CWS/TPU at different strains, inset is enlarged image in the 0-20% compression range; (d) Compressive stress-strain curves of CWS/TPU cycling 5 times at 50% strain

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图 7 CWS/TPU柔性压力传感器的压阻传感性能：(a)传感器结构示意图；(b)传感器在不同压力下的电流响应；(c)循环前后传感器在不同施加压力下电阻的相对变化(ΔR/R₀)；(d)传感器在500 Pa的加载和卸载压力下的响应和恢复时间；(e)传感器的最低检测限；(f)本文CWS/TPU压力传感器的灵敏度与其他文献中三维结构传感器进行对比^{[24; 26; 28-30]}

Figure 7. Piezoresistive sensing performance of CWS/TPU flexible pressure sensor: (a) Schematic diagram of sensor structure; (b) The current response of the sensor at different pressures; (c) The relative change in the resistance of the sensor under different applied pressures (ΔR/R₀) before and after cycle; (d) The response and recovery time of the sensor upon loading and unloading pressure of 500 Pa; (e) The minimum detection limit of the sensor; (f) The sensitivity of the CWS/TPU pressure sensor is compared with other three-dimensional structural sensors^{[24; 26; 28-30]}

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图 8 CWS/TPU传感器的稳定性：(a)传感器超过5000次循环的电阻变化(插图为5000次循环后的三维碳层结构SEM图)；(b)循环后1 kPa压力下传感器在不同放置时间、温度、湿度的电阻相对变化(ΔR/R₀)

Figure 8. The stability of CWS/TPU sensor: (a) Sensing stability of the sensor over 5000 cycles (insert is the SEM image of three-dimensional carbon layer structure after cycling); (b) The relative change in the resistance of the sensor at different placement time, temperature and humidity with 1 kPa pressure after cycling.

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图 9 CWS/TPU传感器在人体健康监测方面的应用：(a)CWS/TPU传感器与LED灯连接的照片，以可视化压缩和释放CWS时的亮度变化(b)指关节弯曲；(c)腕关节弯曲；(d)模拟行走过程；(e)脉搏跳动

Figure 9. Applications of CWS/TPU sensor in human health monitoring: (a) Photographs of the CWS/TPU sensor connected with an LED lamp to visualize the brightness change upon compressing and releasing the conducive sponge. (b) Knuckle bending; (c) Bending of the wrist joint; (d) Simulating the walking process; (e) Pulse beating.

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