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 and properties evaluation

十二烷基硫酸钠(SDS)、十六烷基三甲基溴化铵(CTAB)、壬基酚醚璜基琥珀酸单酯二钠盐(HT A-103)、辛基酚聚氧乙烯醚(OP-10)分别与质量分数为0.1%的多壁碳纳米管(MWCNTs)复配,制备出4种表面活性剂-MWCNTs分散体系。利用UV-Vis光谱、Zeta电位及SEM对其分散性进行了评价,分析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0.30%、0.04%、0.025%、0.06%时体系达到最佳分散效果,分散性能顺序为:CTAB>HT A-103>OP-10>SDS,各体系分散性均随表面活性剂质量分数的升高先增大后减小;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他3种体系;与SDS相比,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。

Sodium dodecyl sulfate(SDS),cetyl trimethyl ammonium bromide(CTAB),nonylphenol ether sulfosuccinate monoester disodium salt(HT A-103)and octaphenyl polyoxyethyiene(OP-10)were compounded with mass fraction of 0.1%of multi-walled carbon nanotubes(MWCNTs)to prepare four kinds of dispersions,respectively.The dispersing properties were evaluated by UV-Vis adsorption spectrum,Zeta potential and SEM.The adsorption modes of different surfactants on the surface of MWCNTs and their effect on dispersion properties were analyzed.The results showed that the best dispersion effect of MWCNTs system was achieved mass fractions of SDS,CTAB,HT A-103 and OP-10 at 0.30%,0.04%,0.025%,0.06%,respectively.The order of dispersibility of surfactants-modified MWCNTs was:CTAB>HT A-103>OP-10>SDS.The dispersibility of all systems first increased and then decreased with the increase of mass fraction of surfactant.Both surface potential and steric hindrance of CTAB-assitied MWCNTs system were higher than those of the other systems,which was attributed to that CTAB molecules could form a double layer adsorption on the MWCNTs through electrostatic force,Van der Waals force,and hydrophobic force.Compared with SDS,HT A-103 could endow MWCNTs with a higher surface potential,and enhance the adsorption properties by virtue of theπ-πinteraction between benzene ring and MWCNTs.