以十二烷基硫酸钠(SDS)为分散剂,采用超声分散法制备了分散性良好的纳米碳纤维(CNFs)悬浮液,结合紫外/可见分光光度计法、Zeta电位法、表面张力测试、透射电镜(TEM)观察、扫描电镜(FESEM)观察和静置离心法,对不同SDS浓度的CNFs悬浮液的均匀性和稳定性进行了表征,同时对SDS的分散机理进行了探讨.实验结果表明,当SDS质量浓度达到1.6 g/L时,CNFs悬浮液的分散稳定性最好,Zeta电位绝对值达到最大,SDS溶液表面张力最低.TEM和FESEM观察发现,分散后的CNFs团聚现象消失,表面有吸附膜形成,证明在分散过程中,SDS会吸附于CNFs表面,使表面张力下降,并通过自身电离产生的静电斥力与疏水链段的空间排斥力共同作用来实现CNFs的分散.
Sodium dodecyl sulfate (SDS) was used as the dispersant and homogeneously dispersed carbon nanofibers (CNFs) suspensions were prepared by sonieation dispersion method.Combined with the UV-visible spectrophotometer,Zeta potential method,surface tension test,transmission electron microscope (TEM),field emission scanning electron microscopy (FESEM) and stewing-centrifugation method,the homogeneity and the stability of CNF suspensions with different SDS concentrations were characterized.And the dispersion mechanism of SDS was also discussed.The experiment results show that,when the concentration of SDS reached 1.6 g/L,the dispersibility of CNF suspensions were the best,the absolute value of Zeta potential reached the maximum and the surface tension of SDS solution was the lowest.TEM and FESEM results show that,the aggregation of CNFs disappeared after dispersion and the adsorption film on the CNFs surface was formed,which well proved that SDS adsorbed on the CNFs surface and decreased the surface tension during the dispersion.Besides,the static repulsive force produced by SDS ionizing and the steric repulsive force between the hydrophobic alkyl chains works together to realize the dispersion of CNFs.