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Three‐dimensional small‐angle neutron scattering of shear‐induced phase separation in a dynamically asymmetric polymer mixture
Author(s) -
Suzuki Junichi,
Koizumi Satoshi
Publication year - 2006
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889806039082
Subject(s) - neutron scattering , scattering , materials science , polystyrene , small angle neutron scattering , phase diagram , polymer , phase (matter) , molecular physics , optics , condensed matter physics , physics , composite material , quantum mechanics
A polymer mixture of polystyrene (PS)/poly(vinyl methyl ether) (PVME) has been investigated by using a three‐dimensional small‐angle neutron scattering (3D‐SANS) method. PS and PVME exhibit a large difference in the glass transition temperature T g . Therefore, dynamical asymmetry is strongly enhanced in an intermediate temperature region between the T g values of neat PS and PVME. In the intermediate temperature region, a shear deformation was imposed on the polymer mixture to enhance the concentration fluctuations, i.e. shear‐induced phase separation. By rotating the film specimen, which was rapidly quenched after deformation, 3D‐SANS due to shear‐induced phase separation was observed successfully. In the q x = q y plane of the sample coordinate system, where q is a component of scattering vector q , it was possible to observe SANS of `double‐lobe' shape, with the minor axes of the lobes inclined towards q x = q y , where q x , q y and q z , denote the shear, velocity gradient and vorticity directions in reciprocal space, respectively. Abnormal `butterfly' scattering was observed in a section cut through the 3D‐SANS in the q x q z plane. The 3D‐SANS thus obtained is discussed in comparison with a model of dynamical coupling between stress and diffusion.