A separation method of responses from large scale motions and chain relaxations for viscoelastic properties of symmetric poly(styrene-b-2-vinylpyridine)s in the ordered state

Separation method of responses from large scale motions and polymer chain motions are investigated for viscoelastic properties of symmetric poly(styrene-b-2-vinylpyridine)s (SP) in the ordered state taking into account of the effects of flow history on the sample. Due to the almost same thermo-rheological properties of components, master curves of dynamic moduli for SP, G*_SP are obtained and shown that the data well coincide with those of polystyrene homopolymers (hPS) at high frequency ω , while responses from large scale motions of lamellar structure, δG*_grain are observed at low ω, which asymptote to δG*_grain ~ ω_0.5. After the pre-shear, magnitude ofδG*_grain became lower at the lower region. When the magnitude of G*SPare appropriately higher than δG*_grain extended to higher ω, δG*_grainand the responses of polymer chains, δG*_chain, having Rouse like modes, are successfully obtained by subtraction, δG*_chain = G*_SP - δG*_grain, irrespective of pre-shear. By combining thus obtained δG*_grain, δG*_chain, and the data for hPS, G*_hPS at higher ω region, G*_SP data can be well approximated in a whole frequency range of the measurement.