College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China.
College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China.
J Colloid Interface Sci. 2018 Feb 15;512:750-757. doi: 10.1016/j.jcis.2017.10.109. Epub 2017 Oct 31.
A promising ionic-gemini molecule, 4, 4'-di (n-tetradecyl) diphenylmethane disulfate salt (DSDM), is reported for effective dispersion of multi-walled carbon nanotubes (MWCNTs) in aqueous medium in the present investigation. The dispersibility and stability of the DSDM-modified MWCNTs were characterized by UV-vis spectrophotometer, Raman spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy and zeta potential measurements. The hydrophobic interaction between alky chains and carbon nanotubes as well as the π-π-stacking interaction between benzene rings and carboatomic rings in MWCNTs enables a successful modification of DSDM onto the MWCNT surface. The dispersed MWCNTs individually existed in dispersion with no structural damage, indicating a much better performance than the MWCNTs dispersed by the sodium dodecylbenzene sulfonate (SDBS), a frequently reported single-chain ionic dispersant. Surface potential measurements showed that the DSDM-modified MWCNTs were negatively charged, giving rise to electrostatic repulsion between the MWCNTs in aqueous solution. A better MWCNT dispersion effect was observed with the increase in MWCNT surface potential, and the dispersion with high MWCNT surface potential presents high dispersion stability with no agglomeration appeared for more than 5 months. The magnesium (Mg) matrix composite fabricated based on the DSDM-dispersed MWCNTs demonstrated excellent mechanical properties compared to pure Mg. Our research may provide an alternative way to improve the mechanical properties of composites.
本研究报道了一种有前景的离子双子分子，4,4'-二（正十四烷基）二苯甲烷二磺酸盐（DSDM），可有效分散在水介质中的多壁碳纳米管（MWCNTs）。通过紫外-可见分光光度计、拉曼光谱、傅里叶变换红外光谱、透射电子显微镜和zeta 电位测量对 DSDM 修饰的 MWCNTs 的分散性和稳定性进行了表征。烷基链与碳纳米管之间的疏水相互作用以及 MWCNTs 中苯环与碳环之间的π-π 堆积相互作用使得 DSDM 成功修饰到 MWCNT 表面。分散的 MWCNTs 以个体形式存在于分散体中，没有结构损伤，表明其性能明显优于经常报道的单链离子分散剂十二烷基苯磺酸钠（SDBS）分散的 MWCNTs。表面电位测量表明，DSDM 修饰的 MWCNTs 带负电荷，导致水溶液中 MWCNTs 之间的静电排斥。随着 MWCNT 表面电位的增加，MWCNT 的分散效果更好，具有高 MWCNT 表面电位的分散体具有高分散稳定性，超过 5 个月没有出现团聚。与纯 Mg 相比，基于 DSDM 分散的 MWCNTs 制备的镁（Mg）基复合材料表现出优异的力学性能。我们的研究可能为改善复合材料的力学性能提供了一种替代方法。
