초록 |
It is commonly believed that conventional incompressible theories for block copolymers along with empirically determined Flory χ are good enough to describe the phase behavior of given copolymer systems. However, the validity of incompressible theory - χ approach counts on the reliability of the fitting function for χ. It is our objective here to give a stringent test for the conventional approach. Taking deuterated dPS-b-PMMA as a model system, which is a typical upper-order-disorder-transition (UODT) system, the empirical Flory χ is first presented for the symmetric copolymer with moderate molecular weight. Using Leibler’s incompressible Landau theory with this χ, ordering transition temperatures for the copolymer with higher molecular weights are then predicted and carefully interpreted. For comparison purposes, we offer Flory χ for the same copolymer using a theory that contains molecular inputs such as self and cross interactions between block components. |