High piezoresistivity and its origin in conducting polyaniline/TiO₂ composites

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• 作者：Somani ; P.R. ; Marimuthu ; R. ; Mulik ; U.P. ; Amalnerkar ; D.P. ; Sainkar ; S.R.
• 关键词：Conducting polymer composites (CPC) ; Polyaniline (PANI) ; Titanium oxide (TiO₂) ; Piezosensitivity (S) ; Space charge limited conduction (SCLC) ; Piezoresistivity (Pr)
• 刊名：Synthetic Metals
• 出版年：1999
• 期刊代码：77_03796779
• 类别：ph
• 出版时间：September 30, 1999
• 卷：106
• 期：1
• 页码：45-52
• 文件大小：788 K

摘要

Highly piezoresistive conducting polyaniline-titanium oxide (PANI/TiO₂) composites have been synthesized by 'in situ' deposition technique by placing the fine grade powder (average particle size of approximately 100 nm) of anatase TiO₂ in the polymerization reaction mixture of aniline. The polyaniline was formed preferentially on the oxide particles giving a much higher yield of polyaniline than in the absence of oxide particles. These composites exhibited high piezosensitivity with the piezosensitivity (S) being maximum at a certain polyaniline/TiO₂ composition. (Our experiments showed that the piezosensitivity is maximum at 35%of polyaniline with piezosensitivity of the order of 10³.) The current-voltage (I-V) characteristics of these composites clearly revealed a non-linear space charge controlled charge transport process. A large hysteresis in these current-voltage (I-V) characteristics is also observed which in turn is found to depend on composite formation (i.e., amount of TiO₂ added). The various results have been explained on the basis of the charge transport mechanism in the heterogenous conducting material having 'dispersed' semiconducting domains dispersed in it.