Maity Arjun, Ray Suprakas Sinha
National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, Pretoria 0001, Republic of South Africa.
J Nanosci Nanotechnol. 2009 Sep;9(9):5223-30. doi: 10.1166/jnn.2009.1136.
In this article, we present the morphology and properties of core-shell nanocomposites of poly(N-vinyl carbazole) (PNVC) with multi-walled carbon nanotubes (MWCNTs). Nanocomposites were synthesized by the in situ solid-state polymerization of N-vinylcarbazole (NVC) at an elevated temperature in the presence of MWCNTs. Fourier transform infrared (FTIR) studies confirmed the ability of MWCNTs to initiate the in situ polymerization of NVC monomers and the presence of PNVC polymer in the nanocomposites. X-ray photoelectron spectroscopy (XPS) studies supported the FTIR results. Field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) images showed the homogeneous covering of MWCNTs outer surfaces by PNVC matrix. The Raman spectroscopy studies also revealed the homogeneous wrapping of MWCNTs outer surfaces without disturbing the inherent electronic structure of MWCNTs. Thermogravimetric analyses revealed a significant improvement of thermal stability of the nanocomposites in the higher temperature region. The core-shell nanocomposites showed interesting fluorescence properties. The dc (direct current) electrical conductivity of pure PNVC dramatically improved after nanocomposites formation with MWCNTs and degree of improvement was dependent on the loading of MWCNTs in the nanocomposites. For example, dc electrical conductivity increased from 10(-16)-10(-12) S x cm(-1) for pure PNVC to approximately 12 S x cm(-1) for nanocomposite containing 50 wt% MWCNTs.
在本文中，我们展示了聚（N-乙烯基咔唑）（PNVC）与多壁碳纳米管（MWCNTs）的核壳纳米复合材料的形态和性能。通过在MWCNTs存在下于高温下原位固态聚合N-乙烯基咔唑（NVC）来合成纳米复合材料。傅里叶变换红外（FTIR）研究证实了MWCNTs引发NVC单体原位聚合的能力以及纳米复合材料中存在PNVC聚合物。X射线光电子能谱（XPS）研究支持了FTIR结果。场发射扫描电子显微镜（FE-SEM）和透射电子显微镜（TEM）图像显示PNVC基质均匀覆盖MWCNTs的外表面。拉曼光谱研究还揭示了MWCNTs外表面的均匀包裹，而不会干扰MWCNTs的固有电子结构。热重分析表明纳米复合材料在较高温度区域的热稳定性有显著提高。核壳纳米复合材料表现出有趣的荧光特性。与MWCNTs形成纳米复合材料后，纯PNVC的直流（direct current）电导率显著提高，且提高程度取决于纳米复合材料中MWCNTs的负载量。例如，纯PNVC的直流电导率从10^(-16)-10^(-12) S·cm^(-1)增加到含50 wt% MWCNTs的纳米复合材料的约12 S·cm^(-1)。
