| 초록 |
We investigated the order to order transition (OOT) of a linear tetrablock copolymer of polystyrene-block-polyisoprene-block-polystyrene-block-polyisoprene (S1I1S2I2) at the symmetric volume fraction of total PS and PI blocks but asymmetry of PI block (τPI = fPI1 /(fPI1+fPI2) = 0.192, in which fPI1 and fPI2 are the volume fractions of PI in the second and forth blocks, respectively). Interestingly, this block copolymer showed cylinder to lamellae morphology transition upon heating. This behaviour is the exactly opposite to commonly observed OOT for linear AB diblock and A1BA2 triblock copolymers with upper critical ordering transition, where lamellae have been transformed to cylinder upon heating. This interesting transition sequence is due to the chain architecture of linear tetra block copolymer with short mid chains. |
