Mesoscopic Simulation on Phase Behavior of Ternary Copolymeric Solution in the Absence and Presence of Shear

摘要

We simulate the microphase separation dynamics of the triblock polymer surfactant (cthylenc oxide)19(propylenc oxide )29elhylene oxide)19 (P65) in aqueous solution by a dynamic variant of mean-field density functional theory for Gaussian chains. With the increase of concentration, different rnesoscalc structures are found in the absence and presence of shear. (1) In the absence of shear, there arc three morphologies formed. The first is the micellar phase,including a sphencaf micelle, which has hexagonal packing and a fcc (face-centered cubic) structure in the solution and a womilike micelle, the second is the bicontinuous phase, which belongs to gyroidtypc connectivity, and the third is the lamellar phase. (2) In the presence of shear, only two morphologies are formed in all concentrations, they are hexagonal and lamellar phases, which align in the flow direction. We notice that the weak shear makes the order parameters of the simulation system oscillate, while the strong shear makes the order parameter get equilibrated in a short time. It is concluded that the mcsoscopic simulation method is a valuable tool for description of mesoscale morphology formation in the absence or presence of shear and can give mesoscale information for the experiments.