探討融熔態 ABCBA 線性五嵌段共聚物於非失措系統之自組裝行為

Abstract

The self-assembly of ABCBA linear pentablock terpolymer melts with non-frustrated interactions of χACN larger than χABN and χBCN are investigated and compared with the corresponding ABC linear triblock terpolymers by three dimensional (3-D) self-consistent field theory (SCFT). In particular, we focus on the effects of the compositions, the interaction parameters, and the number of blocks. Firstly, when the interaction parameters are symmetric (χABN=χBCN) and B is major, both ABC triblocks and ABCBA pentablocks can exhibit intriguing A- and C-formed microstructures in the B-matrix. With decreasing the segregation strength, these various alternating phases can still be observed in the ABC systems. However, due to the chain topology, the A blocks tend to mix with the B blocks in the ABCBA pentablocks, which results in the formation of C-formed structures in the AB-mixed domains. Next, when χABN≠χBCN, in particular at χABN<χBCN, the alternating phases can hardly be formed in these two systems. Aside from the core-shell types structures mainly found in the ABC triblocks, the phase segregation between C and AB-mixed domains can more be discovered in ABCBA. In conclusion, these results not only capture the self-assembling behavior of ISOSI pentablocks, but also provide concrete suggestions for designing the diverse microstructures in the linear ABC-type terpolymers of ABC and ABCBA at non-frustrated interaction parameter regimes.