Determination of the Fddd Phase Boundary in Polystyrene-block-polyisoprene Diblock Copolymer Melts

详细信息    查看全文

• 作者：Myung Im Kim ; Tsutomu Wakada ; Satoshi Akasaka ; Shotaro Nishitsuji ; Kenji Saijo ; Hirokazu Hasegawa ; Kazuki Ito ; Mikihito Takenaka
• 刊名：Macromolecules
• 出版年：2009
• 出版时间：July 28, 2009
• 年：2009
• 卷：42
• 期：14
• 页码：5266-5271
• 全文大小：1036K
• 年卷期：v.42,no.14(July 28, 2009)
• ISSN：1520-5835

文摘

We determined the phase boundary of the Fddd phase in the phase diagram of polystyrene-block-polyisoprene (SI) diblock copolymer by using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). We prepared eight SI diblock copolymers having different volume fractions of polyisoprene, f_PI, in the range of 0.627 ≤ f_PI ≤ 0.653 by living anionic polymerization. At the lowest f_PI, 0.627, SI diblock copolymer showed only the disorder−lamellar (L) transition without any order−order transitions. SI diblock copolymer having the highest f_PI, 0.653, exhibited disorder−gyroid (G)−L transitions with decreasing temperature but did not have the Fddd structure. Except for two samples described above, SI diblock copolymers exhibited disorder−G−Fddd−L transitions with decreasing temperature. It was found that the location of the Fddd region agreed with those obtained by using self-consistent-field theory calculation and Ginzburg−Landau theory.