Block copolymer micelles: Viscoelasticity and interaction potential of soft spheres

被引:69
作者
Buitenhuis, J [1 ]
Forster, S [1 ]
机构
[1] MAX PLANCK INST KOLLOID & GRENZFLACHENFORSCH,D-14513 TELTOW,GERMANY
关键词
D O I
10.1063/1.474346
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
Block copolymer micelles in the size range between 10 and 100 nm are investigated as model systems for soft spheres. The zero shear viscosity eta(0) and complex modulus G* of micellar solutions are studied via dynamic mechanical spectroscopy and shear viscosity measurements over a wide range of concentrations. Depending on their structure, block copolymer micelles exhibit the characteristic rheological behavior of hard spheres, soft spheres, or polymers. With increasing concentration, hard-sphere and most soft-sphere samples exhibit a sharp liquid-solid transition as apparent by a divergence of zero shear viscosity eta(0) and the development of a frequency-independent elastic modulus. The transition occurs at a certain volume fraction which can be related to the softness of the particles. In the solid regime the elastic modulus G' exhibits a characteristic concentration dependence which is related to the spatial variation of the soft sphere repulsive potential. We observe a G'proportional to Z(1.48)r(-2.46) relation between modulus, aggregation number Z and intermicellar distance r which is close to the theoretical prediction G' similar to Z(3/2)r(-2) Of Witten and Pincus derived for polymerically stabilized colloidal particles. (C) 1997 American Institute of Physics.
引用
收藏
页码:262 / 272
页数:11
相关论文
共 67 条