Fabrication of thermo-responsive microcapsule pesticide delivery system from maleic anhydride-functionalized cellulose nanocrystals-stabilized pickering emulsion template.

ABSTRACT

The overuse of pesticides has shown their malpractices. Novel and sustainable formulations have consequently attracted abundant attention but still appear to have drawbacks. Here, we use a maleic anhydride-functionalized cellulose nanocrystals-stabilized Pickering emulsions template to prepare thermo-responsive microcapsules for a pesticide delivery system via radical polymerization with N-isopropyl acrylamide. The microcapsules (MACNCs-g-NIPAM) are characterized by the microscope, SEM, FTIR, XRD, TG-DTG, and DSC techniques. Imidacloprid (IMI) is loaded on MACNCs-g-NIPAM to form smart release systems (IMI@MACNCs-g-NIPAM) with high encapsulation efficiency (~88.49%) and loading capability (~55.02%). The IMI@MACNCs-g-NIPAM present a significant thermo-responsiveness by comparing the release ratios at 35°C and 25°C (76.22% vs 50.78%). It also exhibits advantages in spreadability, retention and flush resistance on the leaf surface compared with the commercial IMI water-dispersible granules (CG). IMI@MACNCs-g-NIPAM also manifest a significant advantage over CG (11.12 mg/L vs 38.90 mg/L for LC50) regarding activity tests of targeted organisms. In addition, IMI@MACNCs-g-NIPAM has shown excellent biocompatibility and low toxicity. All the benefits mentioned above prove the excellent potential of IMI@MACNCs-g-NIPAM as a smart pesticide formulation.