Faiella G, Musto P, Di Florio G, Buosciolo A, D'Orazio L, Antonucci V, Giordano M
Federico II University of Naples, P.le Tecchio 80 80125, Naples, Italy.
J Nanosci Nanotechnol. 2009 Oct;9(10):6026-33. doi: 10.1166/jnn.2009.1561.
The current bottleneck to carbon nanotubes (CNT) application in composite materials field consists in the difficulty of dispersing them in solvents. As a result of strong van der Waals interactions, as produced CNTs are tightly bundled in ropes of several tubes, rendering the carbon-powder insoluble in aqueous and organic liquids and thus unprocessable. The interest in applications that require water-soluble CNTs is growing and much attention is being directed to the study of surfactant aqueous solutions. In a typical dispersion procedure, after the surfactant has been adsorbed on the nanotube surface by hydrophobic or pi-pi interactions, ultrasonication helps nanotubes debundling, providing a mechanical energy able to overcome van der Waals interactions in CNT bundles. The electrostatic repulsion between surfactant polar heads that remain in solution allows the colloidal stability. In this work the dispersibility of HiPCO Single Walled Carbon Nanotubes (SWNT) in different surfactant solutions has been evaluated by using UV-vis and Raman spectroscopies. UV absorbance as well as intensity of SWNTs characteristic Raman bands have been studied as a function of sonication time for each type of surfactant. Moreover the surface morphology of SWNTs films obtained by solutions drying has been observed by using Scanning Electron and Atomic Force Microscopies.
目前碳纳米管（CNT）在复合材料领域应用的瓶颈在于难以将它们分散在溶剂中。由于范德华相互作用很强，所制备的碳纳米管紧密地束状聚集在一起形成由多根管子组成的管束，使得碳粉不溶于水和有机液体，因而无法进行加工处理。对需要水溶性碳纳米管的应用的兴趣日益增长，并且人们正将大量注意力投向表面活性剂水溶液的研究。在典型的分散过程中，表面活性剂通过疏水或π-π相互作用吸附在纳米管表面后，超声处理有助于纳米管解束，提供能够克服碳纳米管束中范德华相互作用的机械能。留在溶液中的表面活性剂极性头之间的静电排斥作用使胶体具有稳定性。在这项工作中，通过紫外可见光谱和拉曼光谱评估了高纯度一氧化碳法单壁碳纳米管（SWNT）在不同表面活性剂溶液中的分散性。针对每种类型的表面活性剂，研究了紫外吸光度以及碳纳米管特征拉曼谱带的强度随超声处理时间的变化。此外，通过扫描电子显微镜和原子力显微镜观察了由溶液干燥得到的碳纳米管薄膜的表面形态。
