阳离子表面活性剂自组织.pdf

物理化学学报( /uli Huaxue Xuebao
August
Acta Phys.-Chim.SFin.2015,31(8),1535-1540
1535
doi:10.3866/PKU.WHXB201506161
www.whxb.pku.edu.cn
尾链长度高度不对称的阴阳离子表面活性剂自组织
董文静赵剑曦
(福州大学化学化工学院胶体界面化学研究所,福州350108)
摘要:通过引进新的溶液制备方法,以光散射、流变、电镜等方法研究了烷烃链长度不对称的阴阳离子表面
活性剂等摩尔混合体系,其中阳离子为二十二烷基三甲基溴化铵(C2TABr),阴离子是烷基羧酸钠(C1 COONA,
n=4,6,8,10,12,14,16)结果表明,烷烃链长度高度不对称时(C22/n4)生成了球状胶束,随着降低不对称度
聚集体向棒状、蠕虫状直至囊泡转变.在构成囊泡的体系中,随着降低链长不对称度,聚集体尺寸明显增大.机
理分析表明,阴阳离子对的几何形状决定了聚集体的形貌以及它们的转变,
关键词:阴/阳离子表面活性剂;烷烃链长不对称度;聚集体形貌;离子对几何
中图分类号:O648
Self-assembly of Cationic/Anionic Surfactants with Highly
Dissymmetric Lengths of Alkyl Tails
DONG Wen-jing ZHAO Jian-xi
(nstitute ofcolloid and Interface Chemist, College of Chemistry and Chemical Engineering, Fuzhou University,
Fuzhou 350108, P R China
Abstract: By introducing a new method of solution preparation, systems of equimolar mixing cationicanionic
surfactants with dissymmetric lengths of alkyl tails were investigated using light scattering, rheology, and
freezing-fracture transmission electron microscopy(ff-tem measurements, in which the cation was
docosyl rimethylammobium bromide( Czt Abr)and the anions were sodium alkylcarboxylates(cm-coona, n
4. 6, 8, 10, 12, 14, 16). The results showed that spherical micelles were favored when the cationicanionic
surfactants had highly dissymmetric length tails (c2/ 4) With decreasing dissymmetry of the alkyl tail
lengths, the aggregates transformed to rod-like micelles, worm-like micelles, and finally vesicles In the
vesicle-formed cases, the size of the aggregate considerably increased with decreasing dissymmetry of the
alkyl tail lengths. By analyzing the mechanism of aggregation, the geometry of the cation/anion pair is thought
to determine the morphology and the transition of aggregates
Key Words: Cat/anionic suractants Diss mmetry of alkyl tail lengths Aggregate morphology
lon-pair geometry
形貌,这既来自不同表面活性剂分子间的协同效应,
元表面活性剂复配往往会加强其自组织的也与二者结合改善了分子几何形状有关.3在二元
能力,也时常由此出现单一组分难以产生的聚集体体系中,阴/阳离子表面活性剂是相互作用最强的
Received: April 16, 2015; Revised: June 15, 2015; Published on Web: June 16, 2015.
ding author Emai
thaocolloid(@fzu.edu.cn;Tel:+86-591-22866338
The project was supported by the National Natural Science Foundation of China(21273040, 21473032
国家自然科学基金(21273040,21473032)资助项目
o Editorial office of Acta Physico-chimica Sinica