Abstract
The effect of hydrostatic pressure ([Formula presented]) on closed-loop phase behavior of deuterated polystyrene-block-poly([Formula presented]-pentyl methacrylate) copolymers [dPS-PnPMA] was investigated by using small-angle neutron scattering and birefringence. For [Formula presented], dPS-PnPMA exhibited a lower disorder-to-order transition temperature ([Formula presented]) at [Formula presented], and then an upper order-to-disorder transition temperature ([Formula presented]) at [Formula presented]. With increasing pressure both [Formula presented] and [Formula presented] were markedly changed, where [Formula presented] was [Formula presented] and [Formula presented] was [Formula presented]. These are consistent with predictions by the Clausius-Clapeyron equation using measured values of the volume and enthalpy changes of both transitions. The large pressure coefficients imply that the closed-loop phase behavior observed for PS-PnPMA is an entropic-driven phase transition.
Original language | English |
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Pages (from-to) | 4 |
Number of pages | 1 |
Journal | Physical review letters |
Volume | 90 |
Issue number | 23 |
DOIs | |
Publication status | Published - 2003 |
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)