ISSN:
0392-6737
Keywords:
Neutron scattering techniques (including small-angle scattering)
;
Polymers, elastomers, and plastics
;
Fluctuation phenomena, random processes and Brownian motion
;
Conference proceedings
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Summary A-B block copolymers in a selective solvent—good for the B-species and bad for the A-species—form micellar aggregates with a compact A-core with a corona (brush) of B «hairs» reaching into the solvent. Whereas polystyrene(PS)-polyisoprene(PI) in decane forms spherical micelles with a PS core of about 10 nm radius, polyethylene(PE)-polyethylenepropylene(PEP) forms micellar platelets, the shape of which is goverend by the habitus of PE crystallites forming the core. These planar aggregates have large (several hundred nanometers) lateral extension and a core thickness in the range of 10 nm. Both systems are model systems for polymer brushes, either on a spherical surface or planar. Neutron spin-echo experiments allow for the investigation of the dynamics of the brushes which reflects their viscoelastic properties. Results of neutron small-angle and spin-echo investigations are reported. The brush dynamics is explained using a model based on an idea of de Gennes describing the brush properties in terms of scaling relations for osmotic pressure and viscosity of a semi-dilute solution with inhomogeneous density.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02456720
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