The sequence of copolymers is of significance to their material properties and phase behavior, yet sequence control in synthetic copolymers remains a challenging objective in polymer science. Greater understanding of the factors which influence sequence development throughout polymerization will aid the development of simple, generalizable methods for sequence control. In previous simulations of solution-based step-growth copolymerizations, we have shown that weak, non-bonding attractions between monomers of the same type produces a microphase separation that is driven by the reaction, altering sequence behavior. This work explores this phenomenon further, examining how the effective attractive interactions, mediated by the relative solvent affinities of the reacting species, impacts the development of sequence and the supramolecular assembly behavior of oligomers in a simple A-B copolymerization. We find that as solvent affinity decreases and the associated self-attractions of monomers increases, self-organization of the reactants causes an emergent shift in reaction kinetics and sequence development. The resulting oligomers show assembly into aggregated structures, characteristic of amphiphilic copolymer self-assembly, and the composition and morphology of these structures are sensitive to the relative balance of affinities between the comonomer species. Our results provide insight into the impact of asymmetric monomer-solvent affinities on sequence development in copolymerization and are of consequence to the informed design of synthetic methods for sequence controlled amphiphilic copolymers.

Asymmetric monomer affinity in step-growth copolymerization: Self-assembly and sequence effects

ACS Spring 2022

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