Statistical Associating Fluid Theory of Homopolymers and Block Copolymers in Compressible Solutions: Polystyrene,Polybutadiene,Polyisoprene,Polystyrene-block-Polybutadiene,and Polystyrene-block-Polyisoprene in Propane

摘要

Polystyrene,polybutadiene,polyisoprene,and their diblock copolymers can form compressible homogeneous solutions in propane that separate upon decompression into a solvent-rich phase and a polymer-rich phase.If the styrene block is large enough,the diblock copolymers can also form a pressure-tunable micellar nanophase that exists below the micellization pressure but above the cloud-point pressure.The onset of micellization and cloud-point transitions can be realistically estimated within a statistical associating fluid theory (SAFT1) framework using universal SAFT1 parameters characteristic of the segment volumes and segment energies,except for the segment-segment interaction energy between the two blocks,which requires an adjustment to account for different types of cloud-point and micellar transitions.