二维层状聚苯胺及其TiO2复合物的制备与光谱学研究

Preparation and Spectral Characterisation of TiO_2/Polyaniline Nanocomposites with 2D Lamellar Morphology

聚苯胺(PANI)是一种具有优良光、电、磁等性能的导电高分子,而TiO2/聚苯胺复合物是结合了聚苯胺和TiO2无机粒子优点的产品。在表面活性剂十二烷基苯磺酸(DBSA)和水形成的微乳液体系中,利用过硫酸铵(APS)将苯胺直接聚合成具有二维层状结构的聚苯胺,进而通过采用钛酸正丁酯水解与苯胺聚合同时进行的策略合成了层状TiO2/聚苯胺复合物。通过扫描电镜图片(SEM)发现二维层状结构的聚苯胺是由大量聚苯胺薄片堆积而成。X射线衍射(XRD)分析表明聚苯胺及其复合物的层间距均为3.4nm,说明这种层状结构极有可能是由DBSA通过协同排列成较为规整的双层分子支撑而成的。傅里叶变换红外谱图(FTIR)说明聚苯胺分子链主要是由苯环和醌环结构组成,拉曼光谱(Raman)和X射线光电子能谱图(XPS)则证明钛酸正丁酯在微乳液体系中水解形成的TiO2具有金红石型结构。紫外可见吸收光谱图(UV-Vis)说明引入无机物TiO2会直接改变导电聚合物分子链的电子跃迁行为。

Nanostructured polyanilines（PANIs） are selected quite often as the matrix for the synthesis of inorganic/conductive polymer composites due to their excellent optical,electrical and magnetic properties.Herein both 2D lamellar PANI and the corresponding composite loading TiO2 species were successfully prepared from a microemulsion system,as composed by dodecyl benzenesulfonic acid（DBSA） and water.The composite was achieved through a simultaneous polymerization of aniline in the presence of ammonium persulfate and hydrolysis of tetrabutyl titanate.Scanning electron microscopy（SEM） images indicate clearly that 2D PANI lamella are formed through organization of small PANI sheets.The inter-lamellar distance of PANI and that of TiO2/polyaniline composite,as derived from X-ray diffraction（XRD）,is about 3.4 nm（nearly twice the length of one DBS molecule）,suggesting that PANI and double-layered DBSA species are arranged in an alternated way.FTIR spectrum displays that PANI chains exhibit quinonoid and benzenoid strutures while both Raman and X-ray photoelectron spectroscopy（XPS） indicate that rutile TiO2 is produced upon hydrolyzation of tetrabutyl titanate in the microemulsion system.Moreover,UV-Vis spectrum suggests that the electronic absorption behaviour of PANI species is influenced upon loading TiO2.