ブロック共重合体の高次構造と粘弾性応答

抄録

We present here a review about our recent studies on relationship between viscoelastic responses and ordered structure, order-disorder transition, and thermal concentration fluctuations (critical fluctuations) of block polymers in condensed state. Brief reviews were first given on order-disorder transition and its characterization by using small-angle X-ray scattering (SAXS) in section 2, and on a relationship between the order-disorder transition and crossover of the flow behavior of block polymers in bulk or concentrated solutions with a neutral solvent in section 3.1. The block polymer solutions with a selective solvent were also discussed in section 3.2 where the two kinds of the thermal transitions (superlattice-ordering or -disordering and the order-disorder transition), their stabilities, and their effects on viscoelastic behavior were discussed. The stability, modulus, and yield stress of the superlattice was proposed to originate from the“entropy elasticity of the confined chains”. In section 4, we discussed the microdomain structure and viscoelastic response in the strong segregation limit, especially the effects of mixing of unlike segments in the domain-boundary region (“domain-boundary mixing”) and in the domains themselves (“mixing-in-domain”) on the viscoelastic behavior in time and temperature scales between the two primary transitions of the block polymers. The domain-boundary relaxation mechanism was proposed and its interpretation was given both from phenomenological and molecular view points. Finally in section 5 was briefly presented a new class of rheo-optical study to elucidate rheology and phase-transition of polymers in condensed state.