表面活性剂分散多壁碳纳米管机理及性能评价

Surfactant-assisted multi-walled carbon nanotubes dispersion: mechanism study and performance evaluation

摘要:

分别以SDS、CTAB、HT A-103、OP-10为分散剂与质量分数为0.1%的多壁碳纳米管（MWCNTs）复配，制备出四种表面活性剂-MWCNTs分散体系。利用UV-vis吸光度、Zeta电位及SEM进行分散性评价，从分子间微观力学角度出发研究了各类表面活性剂在MWCNTs表面的吸附方式以及对分散性能的作用机理和影响规律。结果表明：SDS、CTAB、HT A-103、OP-10质量分数分别在0.3%、0.04%、0.025%、0.055%处体系达到最佳分散效果，分散性能为：CTAB> HT A-103>OP-10>SDS，各体系分散性均随表面活性剂浓度升高先增大后减小；CTAB在静电引力、疏水力及范德华力作用下形成双层吸附紧密吸附包裹在MWCNTs表面，表面电势与空间位阻均高于其余三种体系；相较SDS，HT A-103可赋予MWCNTs更高的表面电势，同时凭借苯环与MWCNTs间的π-π作用增强了吸附性能。

Abstract:

SDS, CTAB, HT A-103 and OP-10 with the concentration of 0.1 wt% were incorperated into multi-walled carbon nanotubes(MWCNTs) dispersions, respectively. And these four surfactant/MWCNTs solutions were treated by ultrasonic waves for further dispersion. After that, the Zeta potential, SEM were employed to characterize the dispersion, revealing the intermolecular micromechanical mechanism. At the same time, the adsorption methods of various surfactants on the surface of MWCNTs and their influence on the dispersion performance were obtained. The results show that: The best dispersion effect of MWCNTs is achieved at the concentration of SDS, CTAB, HT A-103 and OP-10 at 0.3wt%, 0.04wt%, 0.025wt%, 0.055wt%, respectively. And the dispersibility of surfactants-modified MWCNTs is: CTAB>HT A-103>OP-10>SDS; the dispersibility of each system first increases and then decreases with the increase of surfactant concentration. Both surface potential and steric hindrance of surfactants-assitied MWCNTs are higher than the other, in which CTAB molecules can form a double layer adsorption on the MWCNTs through electrostatic force, van der Waals force, and hydrophobic force. Compared with SDS, HT A-103 can endow MWCNTs with a higher surface potential, and enhance the adsorption performance by virtue of the π-π interaction between the benzene ring and the MWCNTs.