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Diffusion in microstructured block copolymer melts
Author(s) -
Lodge Timothy P.,
Hamersky Mark W.,
Milhaupt Jodi M.,
Kannan Rangaramanujam M.,
Dalvi Mukul C.,
Eastman Christine E.
Publication year - 1997
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.19971210119
Subject(s) - copolymer , reptation , diffusion , materials science , rayleigh scattering , chemical physics , polymer chemistry , polymer , glass transition , self diffusion , thermodynamics , chemistry , composite material , optics , physics , self service , marketing , business
Forced Rayleigh scattering has been employed to measure tracer and self‐diffusion in block copolymer melts, for both entangled and unentangled systems, and in both the ordered and disordered states. It is shown that entanglements are particularly effective in retarding the motion of copolymers parallel to the interface between microdomains. The mechanisms of “activated reptation” and “block retraction” are proposed for parallel diffusion. The importance of large amplitude composition fluctuations in the disordered state near the ordering transition is also demonstrated, for both copolymer and homopolymer tracers; the results suggest that copolymer tracers are more affected than homopolymers of comparable molecular weight.