How to Control the Release Behavior of Insect Sex Pheromones Using Nanomicro Fiber: Insights from Experiment and Molecular Dynamics Simulation

Polymer-based electrospun fibers can effectively sustain pheromone release for pest control, yet their regulatory mechanisms remain unclear. In this study, fibers from various polymers were loaded with multicomponent sex pheromones of <i>Grapholitha molesta</i> and characterized. Release tests showed that poly(3-hydroxybutyrate-<i>co</i>-4-hydroxybutyrate) (PHB) fibers released 90% of pheromones in 81.93 days, compared to 14.01 days for polycaprolactone fibers. Molecular dynamics (MD) simulations revealed that pheromones diffused through the polymer network via vibrations, cavity formation, and jumping. PHB fibers exhibited the lowest diffusion coefficient (0.0064 × 10^-9 m² s^-1) and highest activation energy (24.56 kJ mol^-1). Additionally, PHB exhibited good crystallinity and crystal arrangement, thereby enhancing the restriction on pheromone molecules. By combining MD simulations with experimental studies, molecular structure, intermolecular forces, and crystallinity were identified as the main factors regulating the release behavior of these polymer fibers. Finally, trapping experiments confirmed their effectiveness, indicating that release studies can guide field applications.