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

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.