1.
Phys Rev Lett
; 113(6): 068302, 2014 Aug 08.
Artigo
em Inglês
| MEDLINE
| ID: mdl-25148355
RESUMO
Simulations of five different coarse-grained models of symmetric diblock copolymers are compared to demonstrate a universal (i.e., model-independent) dependence of the free energy and order-disorder transition (ODT) on the invariant degree of polymerization NÌ. The actual values of χN at the ODT approach predictions of the Fredrickson-Helfand (FH) theory for NÌ â³ 10(4) but significantly exceed FH predictions at lower values characteristic of most experiments. The FH theory fails for modest NÌ because the competing phases become strongly segregated near the ODT, violating an underlying assumption of weak segregation.