Sustainable Preparation of Microcapsules with Desirable Stability and Bioactivity Using Phosphonium Ionic Liquid as a Functional Additive

A microcapsule is an ideal choice to realize effective utilization of a pesticide and reduce environmental pollution. A novel preparation method of a microcapsule was developed by complex coacervation of phosphonium ionic liquid (PIL) with gelatin. PIL was newly synthesized and used to dissolve and disperse avermectin (Ave) to form stabilized core–shell structure microcapsules by cross-linking with gelatin in a solution. The results demonstrated that avermectin–phosphonium ionic liquid–gelatin (Ave–PIL–Gel) microcapsules had a high Ave entrapment efficiency (approximately 98% w/w), and could effectively enhance the stability of Ave by reducing its degradation in the environment. The Ave release of synthesized Ave–PIL–Gel microcapsules was governed predominantly by non-Fickian diffusion, and the release rates showed positive correlation with the temperature and the base conditions. Compared with the Ave technical solution, the Ave–PIL–Gel microcapsules had better nematicidal activities against plant-parasitic nematodes and showed great potential for sustainable crop protection. The present study provides an improved controlled release formulation comprising a pesticide, which is sensitive to light and easily degradable in soil encapsulated in negatively charged protein, and also provides an environmentally friendly method for preparing the improved pesticide formulation so that the pesticide release rate and release period can be adjustable.