Spontaneous fusion between the vesicles formed by A2n(B2)n type comb-like block copolymers with a semiflexible hydrophobic backbone.

The spontaneous vesicle formation and fusion of A(2n)(B(2))(n) (n = 2-10) type comb-like block copolymers with semiflexible hydrophobic backbone are studied via dissipative particle dynamics (DPD) simulations. By systemically varying the solvent condition, we construct a phase diagram to indicate the thermodynamically stable region for vesicles. The spontaneous fusion between the vesicles is studied, whose mechanism is as follows: first, a stalk is formed between the vesicles; then, the holes appear in both vesicles near the feet of the stalk; finally, the stalk bends to circle the holes and the fusion process is completed. This fusion pathway is similar to that observed in Monte Carlo simulations and dynamic self-consistent filed theory but different from those reported in coarse-grained molecular dynamics and DPD simulations. The main reason for the difference may be attributed to the molecular structures used in different simulation techniques.