Understanding the application of covalent adaptable networks in self-repair materials based on molecular simulation

Cui, Xiang; Zhang, Lu; Yang, Yuliang; Tang, Ping

doi:10.1039/d3sm01364b

Cited by 1 publication

(4 citation statements)

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“…The stickers could form reversible bonds as pairs with other stickers [145]. The thermal activation of sticky bond dissociation suggested exponential behavior over the lifetime of the sticky bond (τ SB ), 1 τ SB ∝exp(−∆E sw /k B T) [127,146,147], in alignment with Kramer's rate theory [148]. Sticky bonds were formed and broken using the Metropolis MC criterion.…”

Section: Hybrid Molecular Dynamics/monte Carlomentioning

confidence: 62%

“…The two different types of CANs, being associative and dissociative, are simulated differently because of their bond exchange mechanism [147,155]. Dissociative CANs are represented simply by two separate MC events, which are the breaking and formation of the bond.…”

Section: Hybrid Molecular Dynamics/monte Carlomentioning

confidence: 99%

“…However, for associative CANs, H is an additional parameter that modulates the reaction's degree of difficulty [155]. Associative CANs exhibit strong mechanical strength and creep resistance, making them suitable for self-adhesion materials [147]. On the other hand, the presence of open stickers in dissociative CANs drives the healing through walking diffusion across the damaged surface [147].…”

Section: Hybrid Molecular Dynamics/monte Carlomentioning

confidence: 99%

“…Associative CANs exhibit strong mechanical strength and creep resistance, making them suitable for self-adhesion materials [147]. On the other hand, the presence of open stickers in dissociative CANs drives the healing through walking diffusion across the damaged surface [147]. Dissociative CANs have a shorter self-healing timescale compared with the self-adhesion timescale of associative CANs [147].…”

Section: Hybrid Molecular Dynamics/monte Carlomentioning

confidence: 99%

See 3 more Smart Citations

Molecular Simulation of Covalent Adaptable Networks and Vitrimers: A Review

Karatrantos,

Couture,

Hesse

et al. 2024

Polymers

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Covalent adaptable networks and vitrimers are novel polymers with dynamic reversible bond exchange reactions for crosslinks, enabling them to modulate their properties between those of thermoplastics and thermosets. They have been gathering interest as materials for their recycling and self-healing properties. In this review, we discuss different molecular simulation efforts that have been used over the last decade to investigate and understand the nanoscale and molecular behaviors of covalent adaptable networks and vitrimers. In particular, molecular dynamics, Monte Carlo, and a hybrid of molecular dynamics and Monte Carlo approaches have been used to model the dynamic bond exchange reaction, which is the main mechanism of interest since it controls both the mechanical and rheological behaviors. The molecular simulation techniques presented yield sufficient results to investigate the structure and dynamics as well as the mechanical and rheological responses of such dynamic networks. The benefits of each method have been highlighted. The use of other tools such as theoretical models and machine learning has been included. We noticed, amongst the most prominent results, that stress relaxes as the bond exchange reaction happens, and that at temperatures higher than the glass transition temperature, the self-healing properties are better since more bond BERs are observed. The lifetime of dynamic covalent crosslinks follows, at moderate to high temperatures, an Arrhenius-like temperature dependence. We note the modeling of certain properties like the melt viscosity with glass transition temperature and the topology freezing transition temperature according to a behavior ruled by either the Williams–Landel–Ferry equation or the Arrhenius equation. Discrepancies between the behavior in dissociative and associative covalent adaptable networks are discussed. We conclude by stating which material parameters and atomistic factors, at the nanoscale, have not yet been taken into account and are lacking in the current literature.

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