Chain diffusion in the melt of an asymmetric diblock copolymer in the disordered and ordered state

被引：12

作者：

Fleischer, G ^{[1
]}

Karger, J ^{[1
]}

Stuhn, B ^{[1
]}

机构：

[1] UNIV FREIBURG,FAK PHYS,D-79104 FREIBURG,GERMANY

来源：

COLLOID AND POLYMER SCIENCE | 1997年 / 275卷 / 09期

关键词：

polymer melt; asymmetric diblock copolymer; polyisoprene-b-polystyrene; disorder-to-order transition; micelles; chain self-diffusion;

D O I：

10.1007/s003960050152

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The self-diffusion in a polystyrene-b-polyisoprene diblock copolymer with a strongly asymmetric composition was investigated with dependence on temperature by pulsed field gradient (PFG) NMR. The diblock shows with decreasing temperature a disorder-to-order-transition at T-ODT = 393 K from a micellar liquid-like to a bcc ordered state which was recently measured by SAXS [M. Schwab and B. Stuhn, Phys. Rev. Lett. (1996) 76: 924]. Two diffusivities were observed, one of the free diblock chains and one of the diblock chains fixed in micelles. The volume fraction of free chains decreases with decreasing temperature. The diffusivity of the free chains must be related to chain stretching. The experiments show that within the time of the NMR experiment (300 ms) there is no exchange between the diblock chains in the free state and those fixed in the core of the micelles.

引用

页码：807 / 813

页数：7

共 25 条

[1] Self-diffusivity of diblock copolymers in solutions in neutral good solvents [J].