| 초록 |
We investigated, the morphology transitions of linear tetrablock copolymers polystyrene-block-polyisoprene-block-polystyrene-block-polyisoprene (S1I1S2I2) by varying volume fraction of I1 block, while maintaining symmetric volume fraction of total PS and PI blocks (fS1+fS2: fI1+fI2 = 1:1). S1I1S2I2 samples were synthesized by sequential anionic polymerization. We observed that when the volume fraction of the I1 block was increased, the microdomains changed as following orders. 1) lamellae (L), 2) asymmetric lamellae (AL), (3) hexagonally packed cylinders of I block, (4) double gyroid, and finally (5) another lamellae (L’). The lamellar domain spacing of L’ was half of that of L, while AL has asymmetric lamellar width of S and I microdomains. Those all transitions were good agreement with self-consistent mean field theory (SCMFT). We observed for the first time the cylindrical and double gyroid microdomains in neat linear block copolymers at symmetric overall volume fraction. |
