Abstract
The order-to-disorder transition (ODT) in a concentrated solution of a polystyrene-polyisoprene diblock copolymer (molecular weights of the polystyrene and polyisoprene blocks are 1.2 × 104 and 1.9 × 104, respectively) in bis(2-ethylhexyl) phthalate is identified by a discontinuous decrease in the static birefringence of the sample upon heating. The location of the ODT is confirmed by rheological measurements; both the storage and loss moduli of the solution show a sharp decrease at the same temperature. Solutions with concentrations ranging from 48 to 61 wt % polymer were examined with the birefringence technique. The measured ODT temperatures for these solutions range from 27 to 178 °C. Small-angle X-ray scattering measurements at temperatures well below the ODT indicate that the ordered solutions have a lamellar microstructure.
Original language | English (US) |
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Pages (from-to) | 3896-3901 |
Number of pages | 6 |
Journal | Macromolecules |
Volume | 25 |
Issue number | 15 |
DOIs | |
State | Published - Jul 1 1992 |