Mesoscopic Simulations of Morphological Transitions of Stimuli-Responsive Diblock Copolymer Brushes

Using coarse-grained DPD simulations, we study the morphology of AB diblock copolymer brushes in selective solvents which are good for the anchored A blocks but poor (of varying degrees measured by the distance from the Theta-point, tau(B)) for B blocks. Choosing appropriate polymer compositions given by the fraction of B blocks, f(B), we find transitions between spherical and cylindrical micelles as well as inverted morphologies (perforated layer). We discuss the phase diagram in the f(B)-tau(B) parameter space and analyze characteristic quantities of the structures obtained such as domain size, periodic spacing and brush height. The internal structure of the uniform (lamellar) structure is investigated in detail. The simulation results are compared with theoretical predictions and experimental observations.