Antony M Jinish, Jayakannan M
Polymer Research Group, Chemical Sciences and Technology Division, National Institute for Interdisciplinary Science and Technology (Formerly: Regional Research Laboratory), Thiruvananthapuram 695019, Kerala, India.
J Phys Chem B. 2007 Nov 8;111(44):12772-80. doi: 10.1021/jp0752670. Epub 2007 Oct 18.
Self-organized micelles of new renewable resource amphiphilic azobenzenesulfonic acid anionic surfactant were utilized to prepare water-soluble, luminescent, and highly ordered polypyrrole nanomaterials. The micellar behavior of the reaction medium was precisely controlled by varying the composition of pyrrole/surfactant ratio from 3 to 100 (up to 100 times lower amount of surfactant with respect to pyrrole), and polypyrrole nanospheres of 150-800 nm were prepared. Dynamic light scattering (DLS) and viscosity techniques were employed as tools to trace the factors, which control the mechanism of polypyrrole nanomaterials formation. DLS studies confirmed that the surfactant exists as in the form of spherical micelles of 4.8 nm diameter in water. Specific viscosity measurement revealed that the pyrrole+surfactant complexes in water exist in the form of either aggregated or isolated micelles depending upon their composition in the feed. SEM and TEM analysis confirmed that the aggregated micellar templates produced coral-like morphology, whereas uniform polypyrrole nanospheres of 150-400 nm were obtained at low micellar concentration. The nanomaterials formation was unperturbed by the variation of the oxidation agents such as ammonium persulphate (APS) or ferric chloride (FeCl3). WXRD analysis of the nanomaterials indicates that the anionic surfactant effectively penetrates into the polypyrrole chains, and a new peak at 2theta = 6.3 degrees (d-spacing = 14 A) was observed corresponding to highly ordered polymer chains. UV-vis and FT-IR confirmed the highly doped state, and the conductivity of the samples was obtained in the range of 10(-1) to 10(-2) S/cm by four-probe conductivity measurements. The azobenzenesulfonic acid anionic surfactant is luminescent in water, and its grafting on the polypyrrole nanospheres enhances the luminescent intensity with the quantum yield in the range of 2 x 10(-3) to 3 x 10(-4).
利用新型可再生资源两亲性偶氮苯磺酸阴离子表面活性剂的自组装胶束制备了水溶性、发光且高度有序的聚吡咯纳米材料。通过将吡咯/表面活性剂的比例从3变化到100（相对于吡咯，表面活性剂的用量最多低100倍）精确控制反应介质的胶束行为，并制备了直径为150 - 800 nm的聚吡咯纳米球。采用动态光散射（DLS）和粘度技术作为工具来追踪控制聚吡咯纳米材料形成机制的因素。DLS研究证实，表面活性剂在水中以直径为4.8 nm的球形胶束形式存在。比粘度测量表明，水中的吡咯 + 表面活性剂络合物根据其进料组成以聚集或孤立胶束的形式存在。扫描电子显微镜（SEM）和透射电子显微镜（TEM）分析证实，聚集的胶束模板产生珊瑚状形态，而在低胶束浓度下获得了直径为150 - 400 nm的均匀聚吡咯纳米球。纳米材料的形成不受氧化剂如过硫酸铵（APS）或氯化铁（FeCl₃）变化的干扰。纳米材料的广角X射线衍射（WXRD）分析表明，阴离子表面活性剂有效地渗透到聚吡咯链中，并且在2θ = 6.3°（d间距 = 14 Å）处观察到一个对应于高度有序聚合物链的新峰。紫外 - 可见光谱（UV - vis）和傅里叶变换红外光谱（FT - IR）证实了高掺杂状态，并且通过四探针电导率测量获得样品的电导率在10⁻¹至10⁻² S/cm范围内。偶氮苯磺酸阴离子表面活性剂在水中发光，并且其接枝到聚吡咯纳米球上增强了发光强度，量子产率在2×10⁻³至3×10⁻⁴范围内。
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