Phase Equilibria in Ternary Blends of Two Linear Homopolymers and A Ring Gradient Copolymer

Phase equilibria in a ternary blend of linear A/B homopolymers of equal sizes and a symmetric A-co-B ring gradient copolymer as an amphiphile with $\alpha $ as the ratio of their chain sizes are investigated in the mean-field picture. The monomer sequence on the copolymer chain is taken as either a step gradient or a fully linear gradient, to which a gradient number $\lambda = $ 0 or 1 is assigned, respectively. Along the isopleth of equal homopolymer amounts, the resultant phase diagrams for the blends are to be built from multicritical points such as Lifshitz or bulk tricritical point depending on $\alpha $ and $\lambda $. The stabilization of lamellar mesophase or its equilibrium with A and B-rich bulk phases is accordingly controllable by the pair of $\alpha $ and $\lambda $.\\[4pt] This work was supported by the Basic Science Research Program (No. 2014023297) from National Research Foundation of Korea. The authors also acknowledge the support from the Center for Photofunctional Energy Materials, which is funded by Gyeonggi Regional Research Center Program (GRRCdankook2011-B01).