Li Xin-Gui, Lü Qiu-Feng, Huang Mei-Rong
Institute of Materials Chemistry, School of Materials Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
Chemistry. 2006 Feb 1;12(5):1349-59. doi: 10.1002/chem.200500486.
A new series of electrically conductive pure copolymer nanoparticles was facilely synthesized by using oxidative polymerization of aniline (AN) and sodium diphenylamine-4-sulfonate (SDP) in acidic media in the absence of stabilizer. The variation of the structure of the copolymer particles was comprehensively studied by carefully choosing several important parameters, such as the comonomer ratio, oxidant/monomer ratio, polymerization time and temperature, monomer concentration, acidic medium, and oxidant species. Analytical techniques used include IR and UV-visible spectroscopy, X-ray diffraction, laser particle analysis, atomic force microscopy, and transmission electron microscopy. It was found that the particle size varied significantly with the above-mentioned polymerization parameters, only changes in the salt concentration in the aqueous testing solution had no noticeable effect. The polymerization conditions were optimized for the formation of copolymer nanoparticles with sought-after properties. The doped copolymer particles of AN/SDP (50:50) at an oxidant/monomer molar ratio of 0.5 exhibit a minimum length of 50 nm and a minimum diameter of 44 nm. The bulk electrical conductivity of the copolymer particles increases greatly from 5.90x10(-4) to 1.15x10(-2) S cm(-1) with increasing AN content. Compared with barely soluble polyaniline, the copolymers exhibit a remarkably enhanced solubility in most solvents, including NH4OH and even water, due to the presence of the hydrophilic sulfonic groups. Nanocomposite films of the nanoparticles and cellulose diacetate exhibit a percolation threshold of down to 0.1 wt %, at which the film retains 98% of the transparency, 94% of the strength, and 5x10(7) times the conductivity of a pure cellulose diacetate film.
通过在无稳定剂的酸性介质中对苯胺（AN）和二苯胺 - 4 - 磺酸钠（SDP）进行氧化聚合，简便地合成了一系列新型导电纯共聚物纳米粒子。通过仔细选择几个重要参数，如共聚单体比例、氧化剂/单体比例、聚合时间和温度、单体浓度、酸性介质以及氧化剂种类，全面研究了共聚物颗粒结构的变化。所使用的分析技术包括红外光谱和紫外 - 可见光谱、X射线衍射、激光粒度分析、原子力显微镜和透射电子显微镜。结果发现，粒径随上述聚合参数显著变化，仅测试水溶液中盐浓度的变化没有明显影响。优化了聚合条件以形成具有所需性能的共聚物纳米粒子。氧化剂/单体摩尔比为0.5时，AN/SDP（50:50）的掺杂共聚物颗粒的最小长度为50 nm，最小直径为44 nm。随着AN含量的增加，共聚物颗粒的体积电导率从5.90×10⁻⁴大幅增加到1.15×10⁻² S cm⁻¹。与难溶性聚苯胺相比，由于存在亲水性磺酸基团，共聚物在包括NH₄OH甚至水在内的大多数溶剂中的溶解度显著提高。纳米粒子与二醋酸纤维素的纳米复合膜的渗滤阈值低至0.1 wt%，此时膜保留了98%的透明度、94%的强度以及比纯二醋酸纤维素膜高5×10⁷倍的电导率。
