Impact of hydrogen bonding interaction energy on the polymerization kinetics of polymerizable deep eutectic solvent monomers†

The fabrication of functional materials through the polymerization of polymerizable deep eutectic solvent monomers (PDES monomers) has emerged as a novel research field in recent years. Besides, in comparison with the isolated polymerization of polymerizable constituents within PDES monomers, PDES monomers manifest elevated conversion and polymerization rates. The magnitude of the action energy of hydrogen bonding, which is an essential influence on the formation of PDES, may have a crucial impact on the kinetic process of PDES monomer polymerization. To delve into the underlying mechanism, this study explores the impact of hydrogen bonding interaction energy on the polymerization kinetics of PDES monomers. This is accomplished using PDES synthesized from an array of quaternary ammonium salt homologs, serving as hydrogen bond acceptors, and acrylic acid, acting as the hydrogen bond donor in a representative capacity. Furthermore, the variations in the physical properties of the deep eutectic polymers derived from PDES monomers are also subject to discussion. In terms of the CC double bond activity during the polymerization of PDES monomers, the investigation reveals that altering the anion, which forms a hydrogen bond through direct coordination, results in a corresponding modification in its hydrogen bonding interaction energy and subsequently impacts the CC double bond activity. Likewise, when the weakly coordinating cation undergoes alteration, the steric effects arising from changes in the cation volume interact with the hydrogen bond, exerting an influence on the CC double bond activity. By delving into the polymerization kinetics of PDES monomers, this research lays the groundwork for regulating the physical and chemical characteristics of PDES, as well as for the design of novel functional materials based on PDES.