Mechanistic Understanding of Sticker Aggregation in Supramolecular Polymers: Quantitative Insights from the Plateau Modulus of Triblock Copolymers
M Nebouy and J Morthomas and C Fusco and L Chazeau and S Jabbari-Farouji and GP Baeza, MACROMOLECULES (2022).
Quantifying the impact of associative group aggregation on the mechanical properties of dense supramolecular networks remains a challenging problem. To address this question, we carry out coarse- grained molecular dynamics simulations of triblock copolymers consisting of a linear succession of hard (crystallizable) and soft (amorphous) segments. This molecular architecture offers the opportunity to increase the volume fraction of crystallites, serving as supramolecular aggregates, in a progressive and controlled fashion, allowing us to study its impact on the plateau modulus of the corresponding thermoplastic elastomers. By unifying these simulations with a recent mechanistic model and experimental data, we provide new quantitative insights into the microscopic origin of the mechanical reinforcement. Enhancement of the plateau modulus originates from the network's topology at low crystallite content (<8 vol %), while it is dominated by the dynamical slowdown of hardened soft segments, which, jointly with the hard phase, form a hybrid percolated network above this threshold.
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