Identification of an intermediate-segregation regime in a diblock copolymer system

We have studied the scaling behavior of the bulk structure in a symmetric diblock copolymer system using small-angle scattering. We have identified a crossover between the inter mediate-segregation regime and the strong-segregation limit at χ N ≃ 29. In the inter mediate-segregation regime (χ N ≃ 5 − 29), the characteristic length scale, D , scales with chain length, N , as D ∝ N 0.83 . In the strong-segregation limit (χ N > 29), the scaling behavior D ∝ N 0.61 is found. The observed crossover is consistent with theoretical predictions.