Next‐Generation Vitrimers Design through Theoretical Understanding and Computational Simulations

Abstract

Vitrimers are an innovative class of polymers that boast a remarkable fusion of mechanical and dynamic features, complemented by the added benefit of end‐of‐life recyclability. This extraordinary blend of properties makes them highly attractive for a variety of applications, such as the automotive sector, soft robotics, and the aerospace industry. At their core, vitrimer materials consist of crosslinked covalent networks that have the ability to dynamically reorganize in response to external factors, including temperature changes, pressure variations, or shifts in pH levels. In this review, the aim is to delve into the latest advancements in the theoretical understanding and computational design of vitrimers. The review begins by offering an overview of the fundamental principles that underlie the behavior of these materials, encompassing their structures, dynamic behavior, and reaction mechanisms. Subsequently, recent progress in the computational design of vitrimers is explored, with a focus on the employment of molecular dynamics (MD)/Monte Carlo (MC) simulations and density functional theory (DFT) calculations. Last, the existing challenges and prospective directions for this field are critically analyzed, emphasizing the necessity for additional theoretical and computational advancements, coupled with experimental validation.

Molecular Simulation of Covalent Adaptable Networks and Vitrimers: A Review

“…While vitrimers are associative CANs, their dissociative counterparts also exist, and fall under the broader umbrella of CANs as well. It is worth noting that a recent review falsely classifies all such networks as vitrimers [50]. The networks that have been investigated in the literature, by atomistic simulation, are depicted in Table 1, and consist of both CANs and vitrimers.…”

“…All previous simulations efforts were based on empirical atomistic force fields, such as CVFF and PCFF, or ReaxFF. However, very recently, a machine-learning (ML) force field (FF) based on density functional theory (DFT) ab initio simulations [50] was developed for polyimine CAN systems (specifically based on dialdehyde and diamine monomers) in order to obtain DFT-level accuracy in energy and atomic force predictions [69]. By combining the ML force field with enhanced sampling methods, including metadynamics and umbrella sampling, the free energy profiles of amine-imine exchange reactions in networks, both with and without water molecules, were calculated [69].…”

“…In that context, the purpose of this thorough review is not to refer to different chemical strategies [31] that can be used to form CANs and vitrimers. Neither is it the goal to explore their behavior by characterization methods or through mesoscale simulations using, for instance, finite element modeling or micromechanical methods [49], nor to review different computational methods [50] to simulate such events. Rather, the focus of this review is the understanding of the unique behavior of CANs and vitrimers from a molecular perspective [51].…”

One-Pot Preparation of Double-Network Epoxy Vitrimers with High Performance, Recyclability, and Two-Stage Stress Relaxation

“…Nonetheless, they suffer from limitations in heat resistance and long-term dimensional stability. Thanks to the pioneering work of Leibler and co-workers, the emergence of vitrimers bridges the gap between the thermosetting plastics and thermoplastics. − With the introduction of associative exchangeable reactions, vitrimers combine the ability to be reshaped, like a thermoplastic, with the permanent set characteristic of a cross-linked network, holding tremendous promise for a range of advanced material technologies. − Subsequent to the transesterification exchange reactions employed in the preparation of epoxy-based vitrimers, different types of dynamic covalent bonding reactions have been developed for preparing vitrimers. These include transesterification, − transcarbamoylation, , imine chemistry, − vinylogous urethane and urea, − disulfide exchange reaction, − silyl-ether exchange, − olefin metathesis reactions, , boronic ester exchange reactions, − and others. − …”