Polydopamine microcapsules from cellulose nanocrystal stabilized Pickering emulsions for essential oil and pesticide encapsulation

The development of microcapsule for crop protection is highly desirable as it reduces environmental pollution, ensures safe handling of pesticides, protects active ingredients (AI) from early degradation as well as increases pest control efficiency. Polydopamine (PDA) microcapsule possesses many attractive properties, such as good adhesion, biodegradability, UV resistance, as well as facile preparation process. However, most preparation methods of PDA capsules rely on either etching the hard templates using harsh acid/solvent or on soft templates containing toxic solvents/emulsifiers, that are not environmentally friendly. In this study, we developed PDA microcapsules templated by Pickering emulsions stabilized by cinnamoyl chloride modified cellulose nano-crystals for essential oil and pesticides encapsulation. The essential oil (turpentine) functions as botanical pesticides as well as solvent for the herbicide (model drug 2,4-D) resulting in high AI encapsulation efficiency. Such system minimizes the use of toxic solvent and synthetic surfactant, improves AI encapsulation efficiency, displays multi-AI encapsulation, adhesive and UV resistance properties, all of which constitute an effective and promising approach for the delivery of agrochemicals for pest control.