Effect of chain architectures on the domain spacing of block copolymers with equivalent segregation degrees

Abstract

It is crucial to lower the domain spacing in the application of directed self-assembly (DSA) of block copolymers. Architectural design of block copolymers provides a possible route. However, the change of the segregation degree is always coupled with that of domain spacing. Therefore, we rescale the segregation degrees of different multiblock copolymers with reference to that of the AB diblock using self-consistent field theory (SCFT), including the [AB]_n linear multiblock, A_nB_n multi-arm star and A_d,nB_d,n dendron-like, such that the density profiles of the lamellar morphology are consistent. Then we compare the lamellar periods of these different copolymers under the condition of equivalent segregation degrees. We find that the star and dendron-like architectures can significantly lower the domain spacing relative to that of the AB diblock, especially when the arm number or the generation number is large. On one hand, our work presents a simple criterion for quantifying the reduction of domain spacing of a specific multiblock architecture relative to that of the AB diblock. On the other hand, our conclusion provides a useful guide for the application of directed self-assembly.