微纳结构柔性压力传感器的制备及应用

柔性压力传感器是一种能够感知或监测外界压力变化的柔性电子器件,具备灵敏度高、形变灵活、制备工艺简单等特点,在可穿戴式电子产品、健康医疗、软体机器人、人机交互等新兴领域具有广泛而重要的应用。灵敏度、检测极限、响应时间与循环工作稳定性是柔性压力传感的核心性能指标,微纳结构的引入对提高柔性压力传感器综合性能具有重要作用。本文根据微纳结构的主要类型介绍了基于微纳结构的柔性压力传感器的最新研究进展,包括各种不同形貌微纳结构对柔性压力传感器性能的影响及其在柔性压力传感器中的应用,并对柔性压力传感器未来的发展提出展望。     

Fast piezoresistive sensor and UV photodetector based on Mn‐doped ZnO nanorods

A low cost hydrothermal synthesis method to synthesize Mn‐doped ZnO nanorods (NRs) with controllable morphology and structure has been developed. Ammonia is used to tailor the ammonium hydroxide concentration, which provides a source of OH^– for hydrolysis and precipitation during the growth instead of HMT. The morphological, chemical composition, structural, and electronic structure studies of the Mn‐doped ZnO NRs show that the Mn‐doped ZnO NRs have a hexagonal wurtzite ZnO structure along the c‐axis and the Mn ions replace the Zn sites in the ZnO NRs matrix without any secondary phase of metallic manganese element and manganese oxides observed. The fabricated PEDOT:PSS/Zn_0.85Mn_0.15O Schottky diode based piezoresistive sensor and UV photodetector shows that the piezoresistive sensor has pressure sensitivity of 0.00617 kPa^–1 for the pressure range from 1 kPa to 20 kP and 0.000180 kPa^–1for the pressure range from 20 kPa to 320 kPa with relatively fast response time of 0.03 s and the UV photodetector has both relatively high responsivity and fast response time of 0.065 A/W and 2.75 s, respectively. The fabricated Schottky diode can be utilized as a very useful human‐friendly interactive electronic device for mass/force sensor or UV photodetector in everyday living life. This developed device is very promising for small‐size, low‐cost and easy‐to‐customize application‐specific requirements. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Piezoresistive effect in p-type polycrystalline diamond films

The piezoresistive effect of boron-doped polycrystalline diamond films was analyzed and discussed by the famous M-S polycrystalline model. It is found that the valence bands splitting-off and the grain-boundary scattering are the main factors responsible for the piezoresistive effect in the p-type polycrystalline diamond films. The gauge-factor calculation formula including the effect of both background scattering and grain-boundary scattering were obtained, and the calculation results are in accordance with the experimental results. Project supported by the National Naturl Sciences Foundation of China (Grant No. 69486001).     

Toward flexible and antibacterial piezoresistive porous devices for wound dressing and motion detectors

Wearable and antibacterial porous devices are promising new multifunctional materials with a wide range of applications in wound dressing and human motion monitoring systems. The deposition of carbon nanotubes and polypyrrole coating on conventional elastomers (polyurethane) is a single‐step procedure that results in a low‐cost, highly conductive, and flexible piezoresistive material with pressure sensitivity of 0.09 kPa⁻¹, Gauge Factor of −10.3, high stability in response to different mechanical efforts and reversible netlike microcracks formation under moderate stretching deformation. The resulting porous material provides direct detection of simple movements from human joints (knee, finger, and elbow) and intrinsic antibacterial activity against Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1063–1072     

三轴压阻微加速度计的结构力学分析

为了提高三轴加速度计机械精度和加工过程中硅片的一致性,设计了基于SOI的单质量块四边八梁结构的三轴加速度计。通过连接扩散在梁上的压敏电阻构成得惠斯通电桥检测三个方向的加速度信号。电桥设计为开环形式,并给出三个方向的电桥输出。结合材料力学和振动力学中的相关理论,建立了结构的数学模型,并对其进行了系统的力学分析,从而得出结构参数对加速度计的一阶固有频率、灵敏度等性能的影响。利用有限元ANSYS仿真软件对结构模型进行了静态和模态分析,验证了力学分析的正确性。最后设计了八张版图及一套可行的工艺流程并加工出加速度计裸片。该微加速度计可同时检测三维加速度矢量,且电桥和结构的设计均较好的抑制了横向效应。     

Structured elastomeric submillimeter films displaying magneto and piezo resistivity

Structured elastomer films (100–150 µm) presenting piezo and magneto resistance are described. The films are composites of filler particles, which are both electrically conductive and magnetic, dispersed in an elastomeric matrix. The particles consist of magnetite (6 nm) grouped in silver‐coated aggregates (Fe₃O₄@Ag). The matrix is styrene–butadiene rubber (SBR) in which diethylene glycol (DEG) is added. The particles, SBR and DEG, are dispersed in toluene and then placed between two rare earth magnets. Formation of pseudo‐chains (needles) of inorganic material aligned in the direction of the magnetic field is obtained after solvent evaporation. The addition of DEG is substantial to obtain an electrically conductive material. The electrical conductivity is anisotropic and increases when applying normal stresses and/or magnetic fields in the direction of the needles. The elastomers, particles, and needless were characterized by XRD, SEM, EDS, FTIR, DSC, TGA, VSM, profilometry, and stress–strain analysis. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 574–586