Micellization in aqueous solution of an ethylene oxide-propylene oxide triblock copolymer, investigated with H-1 NMR spectroscopy, pulsed-field gradient NMR, and NMR relaxation
文献类型：期刊论文
| 作者 | Ma, Junhe; Guo, Chen; Tang, Yalin; Xiang, Junfeng; Chen, Shu; Wang, Jing; Liu, Huizhou |
| 刊名 | JOURNAL OF COLLOID AND INTERFACE SCIENCE
 |
| 出版日期 | 2007-08-15 |
| 卷号 | 312期号:2页码:390-396 |
| 关键词 | PEO-PPO-PEO triblock copolymer micellization H-1 NMR diffusion NMR NMR relaxation |
| ISSN号 | 0021-9797 |
| 其他题名 | J. Colloid Interface Sci. |
| 中文摘要 | H-1 nuclear magnetic resonance (NMR) spectroscopy has been applied to study the temperature and concentration-induced micellization of a poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) triblock copolymer, Pluronic P105, in D2O solutions in the temperature range from 5 to 45 degrees C and the concentration range from 0.01 to 15% (w/v). The intrinsic probes, the chemical shift, and the half-height width of the PO -CH3 signal are very sensitive to the local environment and can be used to characterize the temperature and concentration-dependent aggregation process. When the temperature approaches the critical micellization temperature or the polymer concentration reaches the critical micellization concentration, the chemical shift of the PO -CH3 signal moves toward lower ppm values and the half-height width of the PO -CH3 signal shows a sudden increase. It indicates that the methyl groups are experiencing a progressively less polar environment and transferring from water to the hydrophobic micellar core. The hydrodynamic radius of the unimers and the micelles are determined as be 1.8 and 5.0 nm by means of pulsed-field gradient spin-echo (PGSE) NMR. They were independent of temperature and concentration. The drastic shortening of spin-lattice relaxation time T-1 for the PO -CH3/-CH2- protons in the transition region suggested that the PPO blocks are located in a "liquid-like" micellar core, whereas the exponential increase of T-1 for the PEO -CH2- protons implied that the PEO blocks are still keeping in contact with surrounding water. Thermodynamics analysis according to a closed association model shows that the micellization process is entropy-driven and has an endothermic micellization enthalpy. (c) 2007 Elsevier Inc. All rights reserved. |
| 英文摘要 | H-1 nuclear magnetic resonance (NMR) spectroscopy has been applied to study the temperature and concentration-induced micellization of a poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) triblock copolymer, Pluronic P105, in D2O solutions in the temperature range from 5 to 45 degrees C and the concentration range from 0.01 to 15% (w/v). The intrinsic probes, the chemical shift, and the half-height width of the PO -CH3 signal are very sensitive to the local environment and can be used to characterize the temperature and concentration-dependent aggregation process. When the temperature approaches the critical micellization temperature or the polymer concentration reaches the critical micellization concentration, the chemical shift of the PO -CH3 signal moves toward lower ppm values and the half-height width of the PO -CH3 signal shows a sudden increase. It indicates that the methyl groups are experiencing a progressively less polar environment and transferring from water to the hydrophobic micellar core. The hydrodynamic radius of the unimers and the micelles are determined as be 1.8 and 5.0 nm by means of pulsed-field gradient spin-echo (PGSE) NMR. They were independent of temperature and concentration. The drastic shortening of spin-lattice relaxation time T-1 for the PO -CH3/-CH2- protons in the transition region suggested that the PPO blocks are located in a "liquid-like" micellar core, whereas the exponential increase of T-1 for the PEO -CH2- protons implied that the PEO blocks are still keeping in contact with surrounding water. Thermodynamics analysis according to a closed association model shows that the micellization process is entropy-driven and has an endothermic micellization enthalpy. (c) 2007 Elsevier Inc. All rights reserved. |
| WOS标题词 | Science & Technology ; Physical Sciences |
| 类目[WOS] | Chemistry, Physical |
| 研究领域[WOS] | Chemistry |
| 关键词[WOS] | PEO BLOCK-COPOLYMER ; LIGHT-SCATTERING ; AGGREGATION BEHAVIOR ; ASSOCIATION BEHAVIOR ; MICELLE FORMATION ; WATER ; SURFACTANT ; DIFFUSION ; TEMPERATURE ; SYSTEMS |
| 收录类别 | SCI |
| 原文出处 | |
| 语种 | 英语 |
| WOS记录号 | WOS:000247838300024 |
| 公开日期 | 2013-10-15 |
| 版本 | 出版稿 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/3409]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 作者单位 | 1.Chinese Acad Sci, Grad Sch, Lab Separat Sci & Engn, State Key Lab Biochem Engn,Inst Proc Engn, Beijing 100080, Peoples R China 2.Chinese Acad Sci, Inst Chem, Beijing 100080, Peoples R China |
| 推荐引用方式 GB/T 7714 | Ma, Junhe,Guo, Chen,Tang, Yalin,et al. Micellization in aqueous solution of an ethylene oxide-propylene oxide triblock copolymer, investigated with H-1 NMR spectroscopy, pulsed-field gradient NMR, and NMR relaxation[J]. JOURNAL OF COLLOID AND INTERFACE SCIENCE,2007,312(2):390-396. |
| APA | Ma, Junhe.,Guo, Chen.,Tang, Yalin.,Xiang, Junfeng.,Chen, Shu.,...&Liu, Huizhou.(2007).Micellization in aqueous solution of an ethylene oxide-propylene oxide triblock copolymer, investigated with H-1 NMR spectroscopy, pulsed-field gradient NMR, and NMR relaxation.JOURNAL OF COLLOID AND INTERFACE SCIENCE,312(2),390-396. |
| MLA | Ma, Junhe,et al."Micellization in aqueous solution of an ethylene oxide-propylene oxide triblock copolymer, investigated with H-1 NMR spectroscopy, pulsed-field gradient NMR, and NMR relaxation".JOURNAL OF COLLOID AND INTERFACE SCIENCE 312.2(2007):390-396. |
入库方式： OAI收割
来源：过程工程研究所
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