ISSN:
0392-6737
Schlagwort(e):
Neutron scattering techniques (including small-angle scattering)
;
Macromolecular and polymer solutions (solubility, swelling, etc.)
;
polymer melts
;
Solid-fluid interfaces
;
Structure and morphology
;
thickness
;
Conference proceedings
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Physik
Notizen:
Summary In this paper, we summarize our cumulative work on neutron reflectivity studies of polystyrene-poly(vinyl-2-pyridine) (PS-PVP) and polystyrene-polyethylene oxide (PS-PEO) adsorbed at a quartz-solvent interface. Deuterated toluene was chosen as the solvent since it is a good solvent for PS and a poor one for either of the other two blocks. In this case, the polystyrene dangles into the solvent while the other block acts as an anchor. The neutron reflectivity studies reveal that the form of the polymer density profile normal to the substrate may be varied from an extended «brush» to a condensed «mushroom» conformation by manipulating the ratio of the molecular weights of the two blocks. In addition, we present new data on the PS-PEO system in a poor solvent, deuterated cyclohexane, under conditions of shear flow in Poiseuille geometry. We find that when the PS-PEO diblock is absorbed from cyclohexane and is allowed to relax, the PS chain takes on a «mushroom» conformation. However, when the shear is applied, the layer shear thickens due to the PS chains extending to nearly twice their original lengths.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF02456717
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