Development of gas sensor from conducting polymer composite containing poly (3,4-ethylenedioxythiophene)

This research aims to study film processing of the conducting polymer composites containing poly(3,4-ethylenedioxythiophene) (PEDOT) using solid state polymerization of 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) in the polymer matrix on the interdigitated electrode (IDE) for gas sensing applications. The most appropriate condition for preparing DBEDOT-containing composite film was to spin casting the mixed solution of polybutadiene (PB) and DBEDOT dissolved in toluene at 1:10 (w/w) of PB:DBEDOT on IDE with a spin speed of 1500 rpm for 60 sec, and induced SSP of DBEDOT to conductive PEDOT by heating the PB/DBEDOT composite film at 60 oC for 8 h. The PB/PEDOT composite film having a resistance of 103 ohm was chosen for testing against a number of volatile chemicals. The resistivity of the PB/PEDOT composite film was systematically changed with the polarity of the chemical. The PEDOT-based sensor gave good responses to polar solvents such as methanol, ethanol, and water. The repeatability and sensitivity of the developed sensor were also determined.

本研究旨在面向气体传感应用，探究在叉指电极（interdigitated electrode，IDE）的聚合物基体中，通过2,5-二溴-3,4-乙撑二氧噻吩（2,5-dibromo-3,4-ethylenedioxythiophene，DBEDOT）的固相聚合（solid state polymerization）工艺，制备含聚(3,4-乙撑二氧噻吩)（poly(3,4-ethylenedioxythiophene)，PEDOT）的导电聚合物复合薄膜。制备含DBEDOT复合薄膜的最优工艺条件为：将聚丁二烯（polybutadiene，PB）与DBEDOT按质量比1:10（PB:DBEDOT，w/w）溶解于甲苯中得到混合溶液，随后在IDE基底上以1500 rpm的转速旋涂60秒，再将所得PB/DBEDOT复合薄膜置于60 ℃环境中加热8小时，诱导DBEDOT发生固相聚合，转化为导电PEDOT。本研究选取电阻为10³欧姆的PB/PEDOT复合薄膜，针对多种挥发性化学品开展性能测试，结果显示PB/PEDOT复合薄膜的电阻率随被测化学品的极性呈现系统性变化规律，该PEDOT基传感器对甲醇、乙醇、水等极性溶剂具备良好的响应特性，同时本研究还测定了所开发传感器的重复性与灵敏度。