pH- and concentration-induced micelle-to-vesicle transitions in pyrrolidone-based Gemini surfactants
| Autor: | You-Ru Du, Maili Liu, Zan Jiang, Ke Sun, Jun Liu, Xuefeng Li, Shizhen Mao, Jinfeng Dong |
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| Rok vydání: | 2014 |
| Předmět: |
Aqueous solution
Polymers and Plastics Chemistry Vesicle Inorganic chemistry Cationic polymerization Ethylenediamine Protonation Micelle Fluorescence spectroscopy Crystallography chemistry.chemical_compound Colloid and Surface Chemistry Dynamic light scattering Materials Chemistry Physical and Theoretical Chemistry |
| Zdroj: | Colloid and Polymer Science. 292:739-747 |
| ISSN: | 1435-1536 0303-402X |
| DOI: | 10.1007/s00396-013-3145-0 |
| Popis: | The self-assembly of novel Gemini surfactants with pyrrolidone head groups, N,N'-dialkyl-N,N'-di(ethyl-2-pyrrolidone) ethylenediamine (Di-C (n) P, where n = 6, 8, 10, 12), was studied systematically by employing UV-vis spectroscopy, fluorescence spectroscopy, NMR, dynamic light scattering (DLS), and cryo-transmission electronic microscopy (cryo-TEM) measurements. pH-induced spherical micelle-to-vesicle transitions (MVTs) were observed in all diluted Di-C (n) P aqueous solutions. Spherical micelles were formed when solution pHs were below 7.0, in which Di-C (n) Ps were 1:2 or 1:1 type cationic surfactants, whereas vesicles were formed instead at higher pHs, e.g., pH = 11.0, when Di-C (n) Ps were nonionic type. Apart from the pH-induced MVTs, concentration-induced MVTs were also observed in the protonated Di-C (n) P aqueous solutions due to counterion binding, indicating the presence of a second critical vesicle concentration (cvc) for ionic type Di-C (n) P. Furthermore, the cvc is decreased linearly with the number of carbon atoms n in the hydrophobic tail, following the well-known Stauff-Klevens rule, in the given protonation states. |
| Databáze: | OpenAIRE |
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