Morphologies and Bridging Properties of Graft Copolymers

Morphologies and bridging properties of graft copolymers in the bulk state were studied by using a real-space algorithm of self-consistent field theory in two dimensions. The phase transition from cylindrical to lamellar phase can be triggered by changing the position of graft points and the number of branches. The fraction of bridged conformation, f(bridge), shows a tendency to decrease with increasing the length of free end blocks, tau1, and the number of branches, m. The value of f(bridge) has a discontinuous drop when the transition from cylindrical to lamellar phase takes place. The relationship between m and the number of bridged chains per unit area, nb, which is associated with the mechanical properties of copolymers, was also examined. It was found that nb increases with increasing m in the cylindrical phase. However, in the lamellar phase, nb decreases when m increases. It is proposed that the position of graft points and the number of branches are two important parameters for material design.