Measurement and Predictability of baroplasticity in polystyrene-b-poly(ethyl hexyl acrylate) copolymers

Baroplasticity in deuterated polystyrene-b-poly(ethyl hexyl acrylate) (dPS-b-PEHA) melts is measured through small-angle neutron scattering (SANS) experiments at selected pressures. The order-to-disorder transition (ODT) temperatures for the copolymer is shown to decrease upon the pressure increase. In order to acquire predictability of its phase behaviors, we theoretically analyze our SANS measurements. A compressible random-phase approximation (cRPA) theory based on an off-lattice molecular equation-of-state model is chosen for our purpose. The necessary homopolymer properties for PEHA are first determined by using its PVT data. The ODTs and their pressure dependence for the copolymer are used to elicit a proper cross-interaction parameters between the constituents. We discuss our prediction for the phase behaviors of dPS-b-PEHA/dPS or dPS-b-PEHA/PEHA blends.