Asymmetric Phase Diagram of A(AB)<SUB>3</SUB> Miktoarm Star Copolymer
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초록
내용
We synthesized A(AB)3 Miktoarm star copolymer by using polystyrene (PS) and poly2-vinylpyridine (P2VP). PSL-(PSS-b-P2VP)3 where PSL and PSS are long and short PS chains, respectively, were synthesized by the combination of anionic polymerization, ATRP, and click reaction. We aimed to observe phase changes according to the volume fraction of PS block (fPS) and the chain asymmetry of PS chain (τ=fPS,L/(fPS,L + fPS,S). Phase behavior of PSL-(PSS-b-P2VP)3 was investigated by TEM and SAXS. Interestingly, at a fixed fPS (0.64), an inverted gyroid structure was formed at τ=0.65, while the lamellar structure was observed at τ=0.46. Therefore, we concluded that different nanostructures could be obtained even at the same volume fraction, and for this, it is necessary to achieve high structural asymmetry caused by the large length difference between PSL and PSS.