Structure of grafted polymers, investigated with neutron re#ectometry
- نوع فایل : کتاب
- زبان : انگلیسی
- مؤلف : E.P.K. Currie!,*, M. Wagemaker", M.A. Cohen Stuart!, A.A. van Well"
- چاپ و سال / کشور: 2000
Description
Neutron re#ectometry is used to investigate the structure of polymers end-grafted to an interface at high grafting densities, so-called brushes. Our system consists of polystyrene-polyethyleneoxide (PS-PEO) diblock copolymers, irreversibly adsorbed at the air/D2O interface. At relatively low grafting densities the density pro"le of a monodisperse brush is block-like, with a tail region in which the density smoothly decays towards zero. At high grafting density the pro"le is predominantly parabolic. Bimodal brushes are examined for several length ratio's and mixing ratio's. At a given grafting density the extension of the long chains is larger in a bimodal brush than in a monodisperse. This additional extension increases with increasing length and fraction of small chains. Good agreement is found between the density pro"les obtained from analysis of the neutron re#ectometry data and pro"les predicted by the Scheutjens}Fleer self-consistent-"eld model.
Physica B 283 (2000) 17-21
