Small Angle X-ray Scattering Study on Phase Transition Behavior from Crystalline-Amorphous Alternative Lamellar Structure to Gyroid Phase of Semicrystalline Block Copolymer Polybutadiene-block-Poly(ε-caprolactone)

Abstract

The phase transition from the crystalline-amorphous alternative lamellar structure (CA-LAM) to Gyroid (Gyr) in polybutadiene-block-poly(ε-caprolactone) was investigated using small angle X-ray scattering. It was found that the phase transition from CA-LAM to Gyr occurred via metastable structure. When the composition of crystalline component was close to the Gyr/hexagonally packed cylinder phase boundary in a phase diagram, the hexagonal structure was first observed as a intermediate structure. On the other hand, when the composition was close to the Gyr/lamellar phase boundary, the layer structure was first formed as an intermediate structure. These results indicate that the regularity of this intermediate structure was dependent on the composition of the crystalline component.