Loop and Bridge Conformations of ABA Triblock Comb Copolymers: A Conformational Assessment for Molecular Composites

Abstract

We computationally investigate the conformational behavior, "bridging" chain, between different the phase-separated domains vs "looping" chain on the same domain, for two chain architectures of ABA triblock copolymers, one with a linear architecture (L-TBC) and the other with comb architecture (C-TBC) at various segregation regimes using dissipative particle dynamics (DPD) simulations. The power-law relation between the bridge fraction (Phi) and the interaction parameter (chi) for C-TBC is found to be Phi similar to chi(-1.6) in the vicinity of the order-disorder transition (chi(ODT)), indicating a drastic conversion from the bridge to the loop conformation. When x further increases, the bridge-loop conversions slow down to have the power law, Phi similar to chi(-0.)(18), approaching the theoretical power law Phi similar to chi(-1/9) predicted in the strong segregation limit. The conformational assessment conducted in the present study can provide a strategy of designing optimal material and processing conditions for triblock copolymer either with linear or comb architecture to be used for thermoplastic elastomer or molecular nanocomposites.