Ordered-bicontinuous-double-diamond structure in block copolymer/homopolymer blends
1 Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
2 Graduate School of Engineering, Department of Materials Science & Technology, Nagoya Institute of Technology Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
Received: 15 February 2015
Accepted: 18 May 2015
The morphologies of the microdomain structures in polystyrene-polyisoprene (PS-PI) diblock copolymer and polyisoprene (PI) homopolymer blends were investigated by small-angle X-ray scattering. The PS-PI investigated in the present study has number-average molecular weight and volume fraction of PI , and PI has . The weight fraction of added homopolymer was 0.17. We demonstrated that the existence of ordered-bicontinuous-double-diamond (OBDD) structure was explicitly identified in the PS-PI/PI blend by the scattering method. It was confirmed that OBDD microdomain changed to gyroid (Gyr) when the sample was heated, and the order-order transition between OBDD and Gyr thermo-reversibly occurred. The kinetics of the transformation between OBDD and Gyr was also investigated. In this study, the intermediate structure during the transition between OBDD and Gyr was not observed. A comparison between the rates of transformation revealed that the rate of the OBDD to Gyr transformation is faster than that of the Gyr to OBDD.
PACS: 81.16.Dn – Self-assembly / 82.35.Jk – Copolymers, phase transitions, structure / 83.80.Uv – Block copolymers
© EPLA, 2015