Hydrogen bond-mediated reversible BHT/PVA nanocarriers integrating sustained release kinetics and small-size synergy for potentiated pesticide stability and longevity

The preparation of pesticide-loaded microcapsules using biodegradable polymers and the balance between their sustained-release performance and small-size effects represent an effective strategy to enhance pesticide utilization efficiency. This study devised a one-step sol-gel self-assembly approach to fabricate abamectin-loaded microcapsules using biodegradable polyvinyl alcohol (PVA) and butylated hydroxytoluene (BHT) as raw materials. The results demonstrated that the reaction through hydrogen bonding by PVA and BHT at the o/w interface could generate shells and encapsulate pesticides to make microcapsules. Increasing PVA usage could reduce the particle size and enhance shell stability. The addition of BHT also improved the shell structure stability and encapsulation efficiency, whereas 3 %–7 % concentrations impeded the formation of the shell structure. Abamectin, which has a self-polymerizing ability, also increases microcapsule stability. A 54 °C temperature increase was maintained for 24 h to induce emulsion separation. Subsequent cooling and agitation prompts the reconstitution of pesticide-loaded microcapsules. The synergistic effect of the water-responsive mechanism, high encapsulation efficiency, and thicker shells endows nano-formulations with superior sustained-release performance compared to micro-scale formulations. The photostability of abamectin nanocapsules is significantly enhanced by 68.26 % compared to conventional suspensions, and the content of active ingredients remains at 50.54 % after 60 h of release under light conditions. Owing to their nanoscale sustained-release characteristics, their biological safety is improved by 36.43 %. The encapsulated Aba@BHT-PVA nano-system, leveraging excellent rainwater erosion resistance and leaf surface affinity, significantly prolongs its leaf retention time. Synergizing with the small-size effect, it demonstrates substantial enhancement in both the control efficacy and persistence against Plutella xylostella. Owing to its unique properties and easy regulation, this fabrication technique has great application value in the future.