中国物理B ›› 2009, Vol. 18 ›› Issue (2): 652-657.doi: 10.1088/1674-1056/18/2/043

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Enhanced piezoresistivity in Ni--silicone rubber composites

王少祥1, 常方高2, 杨枫2, 张娜2, 宋桂林2   

  1. (1)College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007, China; (2)College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007, China
  • 收稿日期:2008-08-11 修回日期:2008-08-31 出版日期:2009-02-20 发布日期:2009-02-20
  • 基金资助:
    Project supported by National Natural Science Foundation of China (Grant No 60571063), and partially sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.

Enhanced piezoresistivity in Ni--silicone rubber composites

Chang Fang-Gao(常方高)†, Yang Feng(杨枫), Wang Shao-Xiang(王少祥), Zhang Na(张娜), and Song Gui-Lin(宋桂林)   

  1. College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007, China;
  • Received:2008-08-11 Revised:2008-08-31 Online:2009-02-20 Published:2009-02-20
  • Supported by:
    Project supported by National Natural Science Foundation of China (Grant No 60571063), and partially sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.

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摘要： This paper reports that the nickel--silicone rubber composites with enhanced piezoresistivity were synthesized with much reduced nickel concentration. A large piezosensitivity of 0.716/kPa and a gauge factor of 600 have been obtained for a composite sample with filler-polymer ratio of 2.7:1 by weight. Measurements of resistance as a function of uniaxial force reveal that the piezoresistance arises predominantly from the internal heterogeneity of the material and the effect of geometrical changes of samples under pressure is neglectably small. The nonlinear current--voltage characteristic of the composite depends strongly on the filler content, the initial compression and the electrical current flowing in the sample. Ohmic behaviour has been observed only in the highly compressed samples. The breakdown strength decreases with increasing filler content of the composite. Both I-V and R-f characteristics indicates that the resistivity of the composites decreases with electrical field, suggesting that the composite may also be used to make voltage sensitive resistors for protecting circuits. All the experimental results favour a quantum tunnelling mechanism of conductivity. It finds that the concept `negative resistance', often used to describe the phenomena that current decreases with increasing voltage, is not appropriate and should be avoided.

关键词: piezoresistivity, quantum tunnelling, I-V characteristics, voltage sensitive resistors

Abstract: This paper reports that the nickel--silicone rubber composites with enhanced piezoresistivity were synthesized with much reduced nickel concentration. A large piezosensitivity of 0.716/kPa and a gauge factor of 600 have been obtained for a composite sample with filler-polymer ratio of 2.7:1 by weight. Measurements of resistance as a function of uniaxial force reveal that the piezoresistance arises predominantly from the internal heterogeneity of the material and the effect of geometrical changes of samples under pressure is neglectably small. The nonlinear current--voltage characteristic of the composite depends strongly on the filler content, the initial compression and the electrical current flowing in the sample. Ohmic behaviour has been observed only in the highly compressed samples. The breakdown strength decreases with increasing filler content of the composite. Both I-V and R-f characteristics indicates that the resistivity of the composites decreases with electrical field, suggesting that the composite may also be used to make voltage sensitive resistors for protecting circuits. All the experimental results favour a quantum tunnelling mechanism of conductivity. It finds that the concept `negative resistance', often used to describe the phenomena that current decreases with increasing voltage, is not appropriate and should be avoided.

Key words: piezoresistivity, quantum tunnelling, I-V characteristics, voltage sensitive resistors

中图分类号:  (Low-field transport and mobility; piezoresistance)

  • 72.20.Fr
72.80.Tm (Composite materials) 73.40.Gk (Tunneling) 81.05.Qk (Reinforced polymers and polymer-based composites)