电化学制备聚合物膜用于pH传感的研究

Study on Electrochemical Prepared Polymer in PH Sensing

苯胺单体和吡咯单体分别溶解在1 mol/L的稀硫酸溶液中,采用循环伏安法,在电化学工作站三电极体系中的工作电极上电聚合制备出掺杂有SO2-4离子的聚苯胺和聚吡咯薄膜。通过优化单体物质的量、扫描速率和扫描圈数等条件制备出对pH值呈现灵敏度最高的薄膜。使用傅里叶转换红外光谱分析仪(FTIR)、扫描电镜(SEM)对薄膜的结构和形貌进行表征和分析。聚苯胺和聚吡咯薄膜作为基于FET装置中分离式扩展栅上的pH敏感膜在pH为2~10标准缓冲液中呈现出的最高灵敏度分别为51.05 m V/pH、47.15 m V/pH,并具有良好的线性关系(R_2=0.99)以及较小的滞后电压(6 m V、2 m V)和较短的响应时间(6 min、5 min)。结果表明:容易制备的聚苯胺和聚吡咯薄膜加以修饰可用于pH传感,并且可以结合生物分子应用于基于FET的生物传感器。

Aniline and pyrrole monomer were dissolved in dilute sulfuric acid solution （1 mol/L）, polyaniline and polypyrrole films doped with SO4^2- prepared on the working electrode of a three-electrode system of electrochemical workstation by cyclic voltammetry. Thin films with best sensitivity were prepared by optimizing conditions including amount of monomer substance ,scanning rate and the number of scanning circle. The structure and morphology of the films were characterized and analyzed by FTIR and SEM.Polyaniline and polypyrrole films were employed as separative extended gate pH sensing membrane in FET-based devices presenting sensitivity at 51.05 mV/pH and 47.15 mV/pH with a good linear relationship （R2 = 0.99）in standard buffer solution with pH from 2 to 10,a small hysteresis voltage （6 mV,2 mV）and short response time （6 rain,5 min）. The results suggest that polyaniline and polypyrrole films can be easily processed to form suitable thin films for pH sensing and combined with biomolecules to be applied in FET-based biosensors.