Periodic Patchy Spheres Self-Assembled by AmBCAn′ Multiblock Terpolymers

We have designed A(m)BCA(n)' multiblock terpolymers and studied their self-assembly using self-consistent field theory, aiming to generate the periodically arranged patchy spheres and thus to clarify the regulation mechanism of the number of patches. A number of two-dimensional phase diagrams are constructed for three typical architectures A(2)BCA(2)', A(2)BCA(3)', and A(3)BCA(2)'. Four kinds of stable patchy spheres with the number of patches as 2 (S-2), 4 (S-4), 5 (S-5), and 6 (S-6) are obtained. These phases follow a common transition sequence of S-2 -> S-4 -> S-5 -> S-6 along with the increasing of the volume fraction of C-block (f(C)), which forms the core sphere patched with B-domains. Moreover, the S-6 phase exhibits the widest stability window, while S-5 has the narrowest one. The increased arms of A'-blocks in A(2)BCA(3)' architecture deflect the phase boundaries toward large f(C) and accordingly expand the regions of these patchy spheres due to the amplified effect of spontaneous curvature. In contrast, the increased arms of A-blocks in A(3)BCA(2)' remarkably expands the window of S-6 but narrows those of the other patchy spheres, which is mainly caused by increased packing frustration resulting from the reduced extension of the more divided A-blocks. The widest window of the S-6 phase reaches Delta f(C) similar to 0.13, which is readily accessed by experiment. Our work not only demonstrates a self-assembly strategy to engineer the patchy spheres, but also sheds light on the regulation mechanism of the patchy number.

Automated summary

We designed A(m)BCA(n) multiblock terpolymers and studied their self-assembly process. We successfully obtained four stable patchy spheres and clarified the regulation mechanism of the number of patches.