Τίτλος:
Phonon propagation in ordered diblock copolymer solutions
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
High-resolution inelastic light scattering was employed to measure the dispersion relations for the acoustic excitations in ordered concentrated solutions of poly(styrene)-block-poly(isoprene) copolymers with both symmetric and asymmetric composition and large spacing (220-415 nm). The morphology is manifested in the rich phonon spectrum recorded for different scattering wave vectors q in the range 0.003-0.034 nm-1. The experimental ωa,(q) of the sth branch is directly compared with the theoretical dispersion from band structure calculations performed for different directions of q in the reciprocal lattice of lamellar and cylindrical periodic structures. The dispersion relations turn out to be a sensitive index of the microphase morphology and the grain orientation.
Συγγραφείς:
Tommaseo, G.
Penciu, R.S.
Fytas, G.
Economou, E.N.
Hashimoto, T.
Hadjichristidis, N.
Περιοδικό:
Macromolecules
Λέξεις-κλειδιά:
Annealing; Block copolymers; Brillouin scattering; Dispersions; Elastic waves; Light scattering; Phonons; Rayleigh scattering; Refractive index; Solutions; Transmission electron microscopy; Vectors; X ray scattering, Elastic constants; Grain orientation; Microphase morphology; Sensitive index, Macromolecules
