修饰Langmuir-Blodget膜法制备聚(3,4-亚乙基二氧噻吩)薄膜结构和导电性能的研究

采用修饰Langmuir-Blodget(LB)膜法以二十烷酸(AA)LB膜为模板,通过3,4-亚乙基二氧噻吩(EDOT)单体在LB膜亲水基团间聚合,制备了二十烷酸/聚(3,4-亚乙基二氧噻吩)(AA/PEDOT)复合LB膜.UV-Vis、FTIR和XPS分析表明EDOT在多层膜中有效聚合,生成了PEDOT导电聚合物;X射线衍射(XRD)和二次离子质谱(SIMS)分析表明薄膜具有较好的层状有序结构,进一步研究发现EDOT在AA多层膜中的聚合破坏了原有LB膜的有序性,这可能与聚合过程对层状结构产生的破坏作用有关;采用四探针仪及半导体测试仪研究了薄膜导电性能,发现AA/PEDOT多层膜的电导率随处理时间的变化产生突变,这与多层膜中导电通道的"逾渗"有关,在有效导电网络连通后电导率发生了突变.测试结果还表明AA层和PEDOT层之间具有较为明显的界面,PEDOT显示出较好的定域性,薄膜具有很好的层状有序结构.

STRUCTURE AND ELECTRIC PROPERTIES OF POLY(3,4-ETHYLENEDIOXYTHIOPHENE) FILMS PREPARED THROUGH MODIFICATION OF LB FILM TEMPLATES

Arachidic acid/poly(3,4-ethylenedioxythiophene) (AA/PEDOT) multilayer films were prepared by modification of AA multilayer Langmuir-Blodget (LB) films.3,4-Ethylenedioxythiophene (EDOT) monomers were introduced into the AA multilayer films and polymerized to form PEDOT layers between the AA layers.Ultraviolet visible spectroscopy (UV-Vis),Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses evidenced the EDOT polymerization in the AA film templates.Analyses of X-ray diffraction and secondary-ion mass-spectroscopy indicated that the final films had a well-arranged lamella structure,and obvious interfaces between the AA and PEDOT layers were detected.Further research showed that the polymerization of EDOT destroyed the orderliness of the original AA multilayer LB film.The four-point probe method and semiconductor testing instruments were used to study the conductivity of the films.It was found that in the process of EDOT polymerization the conductivity of the films exhibited a sudden increase.It was explained as a percolation phenomenon,the sudden increase of conductivity should be related with the formation of an effective conductive network within the AA/PEDOT multilayer films.