| Phase Behavior, Rheological Property, and Transmutation of Vesicles in Fluorocarbon and Hydrocarbon Surfactant Mixtures | |
| Department | 固体润滑国家重点实验室 |
Yuan ZW(苑再武)2; Qin MH(秦梦华)2; Chen XS(陈秀山)2; Liu CC(刘昌程)3; Li HG(李洪光)1 ; Hao JC(郝京诚)3; Li HG(李洪光); Hao JC(郝京诚)
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| 2012 | |
| Source Publication | Langmuir
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| ISSN | 0743-7463 |
| Volume | 28Issue:25Pages:9355-9364 |
| Abstract | We present a detailed study of a salt-free cationic/anionic (catanionic) surfactant system where a strongly alkaline cationic surfactant (tetradecyltrimethylammonium hydroxide, TTAOH) was mixed with a single-chain fluorocarbon acid (nonadecafluorodecanoic acid, NFDA) and a hyperbranched hydrocarbon acid [di-(2-ethylhexyl)phosphoric acid, DEHPA] in water. Typically the concentration of TTAOH is fixed while the total concentration and mixing molar ratio of NFDA and DEHPA is varied. In the absence of DEHPA and at a TTAOH concentration of 80 mmol·L–1, an isotropic L1 phase, an L1/Lα two-phase region, and a single Lα phase were observed successively with increasing mixing molar ratio of NFDA to TTAOH (nNFDA/nTTAOH). In the NFDA-rich region (nNFDA/nTTAOH > 1), a small amount of excess NFDA can be solubilized into the Lα phase while a large excess of NFDA eventually leads to phase separation. When NFDA is replaced gradually by DEHPA, the mixed system of TTAOH/NFDA/DEHPA/H2O follows the same phase sequence as that of the TTAOH/NFDA/H2O system and the phase boundaries remain almost unchanged. However, the viscoelasticity of the samples in the single Lα phase region becomes higher at the same total surfactant concentration as characterized by rheological measurements. Cryo-transmission electron microscopic (cryo-TEM) observations revealed a microstructural evolution from unilamellar vesicles to multilamellar ones and finally to gaint onions. The size of the vesicle and number of lamella can be controlled by adjusting the molar ratio of NFDA to DEHPA. The dynamic properties of the vesicular solutions have also been investigated. It is found that the yield stress and the storage modulus are time-dependent after a static mixing process between the two different types of vesicle solutions, indicating the occurrence of a dynamic fusion between the two types of vesicles. The microenvironmental changes induced by aggregate transitions were probed by 19F NMR as well as 31P NMR measurements. Upon replacement of NFDA by DEHPA, the signal from the 19F atoms adjacent to the hydrophilic headgroup disappears and that from the 19F atoms on the main chain becomes sharper. This could be interpreted as an increase of microfluidity in the mixed vesicle bilayers at higher content of DEHPA, whose alkyl chains are expected to have a lower chain melting point. Our results provide basic knowledge on vesicle formation and their structural evolution in salt-free catanionic surfactant systems containing mixed ion pairs, which may contribute to a deeper understanding of the rules governing the formation and properties of surfactant self-assembly. |
| Subject Area | 材料科学与物理化学 |
| DOI | 10.1021/la301416e |
| Funding Organization | the NSFC (Grant 21033005);the National Basic Research Program of China (973 Program, 2009CB930103);NFS of Shandong Province (2009ZRB01876) |
| Indexed By | SCI |
| If | 4.187 |
| Language | 英语 |
| compositor | 第一作者单位 |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.licp.cn/handle/362003/4753 |
| Collection | 固体润滑国家重点实验室（LSL） |
| Corresponding Author | Li HG(李洪光); Hao JC(郝京诚) |
| Affiliation | 1.Chinese Acad Sci, Lanzhou Inst Chem Phys, State Key Lab Solid Lubricat, Lanzhou 730000, Peoples R China 2.Shandong Polytech Univ, Sch Chem & Pharmaceut Engn, Jinan 250353, Peoples R China 3.Shandong Univ, Minist Educ, Key Lab Colloid & Interface Chem, Jinan 250100, Peoples R China |
| Recommended Citation GB/T 7714 | Yuan ZW,Qin MH,Chen XS,et al. Phase Behavior, Rheological Property, and Transmutation of Vesicles in Fluorocarbon and Hydrocarbon Surfactant Mixtures[J]. Langmuir,2012,28(25):9355-9364. |
| APA | Yuan ZW.,Qin MH.,Chen XS.,Liu CC.,Li HG.,...&郝京诚.(2012).Phase Behavior, Rheological Property, and Transmutation of Vesicles in Fluorocarbon and Hydrocarbon Surfactant Mixtures.Langmuir,28(25),9355-9364. |
| MLA | Yuan ZW,et al."Phase Behavior, Rheological Property, and Transmutation of Vesicles in Fluorocarbon and Hydrocarbon Surfactant Mixtures".Langmuir 28.25(2012):9355-9364. |
| Files in This Item: | ||||||
| File Name/Size | DocType | Version | Access | License | ||
| 5 Langmuir.pdf（1556KB） | 期刊论文 | 作者接受稿 | 开放获取 | CC BY-NC-SA | View Application Full Text | |
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