Time-resolved SANS for the determination of unimer exchange kinetics in block copolymer micelles

被引:96
作者
Willner, L [1 ]
Poppe, A [1 ]
Allgaier, J [1 ]
Monkenbusch, M [1 ]
Richter, D [1 ]
机构
[1] Forschungszentrum Julich, Inst Festkorperforsch, D-52425 Julich, Germany
来源
EUROPHYSICS LETTERS | 2001年 / 55卷 / 05期
关键词
D O I
10.1209/epl/i2001-00467-y
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
A time-resolved SANS method was developed for the determination of unimer exchange kinetics of polymeric micelles under equilibrium conditions. Measurements were performed on the system PEP-PEO/DMF exploiting the large difference in scattering length density of protonated and deuterated species. In contrast to theoretical predictions the observed kinetics consists of two well-separated processes. From temperature-dependent measurements the corresponding activation energies E(A) could be determined. A comparison on the basis of a scaling prediction of Halperin and Alexander indicates that the fast process can be associated with a single unimer insertion/expulsion mechanism. The slow process, on the other hand, could not be explained on the basis of available microscopic models.
引用
收藏
页码:667 / 673
页数:7
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