posted on 2021-09-02, 14:37authored byAnna L. de Marco, Davide Bochicchio, Andrea Gardin, Giovanni Doni, Giovanni M. Pavan
Supramolecular fibers
composed of monomers that self-assemble directionally via noncovalent interactions are ubiquitous in nature, and
of great interest in chemistry. In these structures, the constitutive
monomers continuously exchange in-and-out the assembly according
to a well-defined supramolecular equilibrium. However, unraveling
the exchange pathways and their molecular determinants constitutes
a nontrivial challenge. Here, we combine coarse-grained modeling,
enhanced sampling, and machine learning to investigate the key factors
controlling the monomer exchange pathways in synthetic supramolecular
polymers having an intrinsic dynamic behavior. We demonstrate how
the competition of directional vs. nondirectional
interactions between the monomers controls the creation/annihilation
of defects in the supramolecular polymers, from where monomers exchange
proceeds. This competition determines the exchange pathway, dictating
whether a fiber statistically swaps monomers from the tips or from
all along its length. Finally, thanks to their generality, our models
allow the investigation of molecular approaches to control the exchange
pathways in these dynamic assemblies.