Structural and Transport Properties of Norbornene-Functionalized Poly(vinyl alcohol) “Click” Hydrogel: A Molecular Dynamics Study

The thiol–norbornene cross–linked poly(vinyl alcohol) (PVA) “click” hydrogel is a synthetic and sustainable polymer chain that is widely used in the biomedical field. Molecular dynamics simulations are invoked to measure the hydrogel’s transport and structural properties that cannot be measured precisely by experimental techniques. There are three different forms of thiol–norbornene cross–linked PVA “click” hydrogel models constructed by replicating a representative unit cell of cross–linked PVA chains and immersing it into an aqueous environment. Additionally, the dynamics is compared with the movement of the PVA hydrogel in water. The AMBER14SB force field is utilized to describe the interatomic interactions. The system’s dynamic behavior is achieved in the grand canonical ensemble and the isobaric isothermal ensemble. The dynamics of the system exposes the vital role played by norbornene in securing the stability of PVA polymer chains, thus contributing significantly to the overall robustness of the hydrogel. Delving into the structural analysis of the radial distribution function provides insights into the emergence of compact clusters, where interactions between PVA polymer chains and water drive their formation. The PVA hydrogel functionalizes with norbornene and exhibits a superior swelling ratio compared with the other variant hydrogels considered here owing to the freezing water phenomenon. Conversely, the swelling ratio of the cross–linked PVA hydrogel diminishes due to the intricate process of structural self–assembly. Consequently, the cohesive force within the cross–linked PVA hydrogel structure intensifies, highlighting the profound influence of bolstered hydrogen bonding. The exploration from this study provides valuable insights into the behavior of thiol–norbornene “click” PVA hydrogels and the importance of chemical cross–linking. The thiol–norbornene “click” PVA hydrogel holds tremendous potential for applications across diverse scientific domains, heralding a new era of possibilities.