Enhanced piezoresistivity in Ni--silicone rubber composites
Wang Shao-Xianga, Chang Fang-Gaob, Yang Fengb, Zhang Nab, Song Gui-Linb
a College of Physics and Information Engineering, Henan
Normal University, Xinxiang 453007, China; b College of Physics and Information Engineering, Henan
Normal
University, Xinxiang 453007, China
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.
Received: 11 August 2008
Revised: 31 August 2008
Published: 20 February 2009
PACS:
72.20.Fr
(Low-field transport and mobility; piezoresistance)
(Reinforced polymers and polymer-based composites)
Fund: 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.
Cite this article:
Chang Fang-Gao, Yang Feng, Wang Shao-Xiang, Zhang Na, Song Gui-Lin Enhanced piezoresistivity in Ni--silicone rubber composites 2009 Chin. Phys. B 18 0652
