Regulation Mechanism of Entropy–Enthalpy Compensation Effect on Charge Trap Energy Levels in Hydrogen-Bonded PP- g -MA/PVDF Composites

Hydrogen bonds, due to their directionality and reversibility, are often regarded as a key “dynamic bridge” connecting molecular-scale structural rearrangements with electrical behaviors. However, the stability evolution laws of hydrogen bond networks under temperature perturbations, and how they project onto electronic structures and charge trap energy levels through thermodynamic mechanisms, remain unclear. In this study, using polypropylene- graft -maleic anhydride/polyvinylidene fluoride (PP- g -MA/PVDF) composites as the research object, and combining molecular dynamics simulations with density functional theory calculations, we tracked the formation–breaking–rearrangement process of dynamic hydrogen bond networks and revealed the regulation mechanism of the entropy–enthalpy compensation (EEC) effect on these networks. The results indicate that at 403 K, the increase in conformational entropy and the change in bonding enthalpy reach an optimal balance; the dynamic hydrogen bond network exhibits the optimal geometric configuration (with an average bond length of 1.85 Å and a bond angle of 166°) and the highest stability, inducing stronger electron localization and deepening the charge trap energy level by 0.14 eV. Upon exceeding this temperature, entropy-driven disordering dominates, leading to the rapid disintegration of the hydrogen bond network, and the traps subsequently become shallower. Furthermore, a differential equation model describing the kinetics of hydrogen bond formation/breaking was established, and a physical model constructing the linear correlation between the variation of hydrogen bond interaction energy and the variation of trap energy levels was built. From a unified perspective of thermodynamics and kinetics, this study constructs a physical framework describing the regulation of polymer electronic states and charge trap energy levels by dynamic hydrogen bonds, thereby elucidating the influence mechanism of dynamic hydrogen bonds on polymer charge trap characteristics at a fundamental theoretical level, and providing a theoretical basis for subsequent research in related fields.