Sequence-encoded Conformation Pathways in Viscoelastic Microphase Separation of Multiblock Copolymers

Abstract

Deciphering how molecular sequences of block copolymers program their self-assembly pathways is a pivotal pursuit in polymer science. To this end, we integrated viscoelastic constitutive relations into dynamic self-consistent field theory (DSCFT) to probe the spatiotemporally coupled evolution of nanostructures and chain conformations in sequence-defined multiblock copolymers during viscoelastic microphase separation. The DSCFT simulations reveal that the linear sequence of slow-relaxing “hard” and fast-relaxing “soft” blocks encodes two programmable kinetic motifs: a hard-soft-hard sequence drives a sharp, droplet-coalescence-triggered conversion from loop to bridge conformations during viscoelasticity-mediated phase inversion, whereas a soft-hard-soft sequence governs a gradual, network-contraction-driven relaxation of chain conformations. Serving as modular kinetic codes identified in the system of triblock copolymers, these kinetic motifs were shown to operate concurrently within tetrablock chains and generalize to penta- and hexa-block architectures, demonstrating the scalability and robustness of sequence-encoded dynamics. This work establishes the paradigm of sequence-encoded viscoelastic kinetics, providing a mechanism for controlling pathway-dependent self-assembly at the molecular level.