Abstract: The salt-responsiveness of Pickering emulsions has significantly influenced their applications due to the large amount of salt on the surface of plant leaves. The present study provided a maleic anhydride-functionalized cellulose nanocrystal-stabilized high internal phase Pickering emulsion (MACNCs-HIPPEs) that was stable to high-concentration salt and used for pesticide delivery. The stability of MACNCs-HIPPEs was investigated by adjusting the oil-phase volume fraction (φ), the MACNCs concentration, NaCl dosages, and the rheological properties. The high internal phase Pickering emulsion was obtained at φ of 0.8 and MACNCs concentration of 2wt% and showed excellent salt stability (NaCl, 1200 mM) and significant storage stability (60 days). The sustained release of imidacloprid (IMI) from imidacloprid-loaded MACNCs-HIPPEs (IMI@MACNCs-HIPPEs) showed a positive correlation to the temperature (15 ◦ C, 25 ◦ C, 35 ◦ C), indicating clear thermo-responsiveness of the prepared pesticide formulation. The test of spread and retention of IMI@MACNCs-HIPPEs on the leaf surface showed a significant advantage compared with the commercial IMI water dispersible granules (CG). All the advantages mentioned above showed the excellent potential of the MACNCs-HIPPEs in delivering lipophilic pesticides.
Keywords: Pesticide delivery, High internal phase Pickering emulsion, Cellulose
