Salinity-Driven\nInterface Self-Assembly of a Biological\nAmphiphilic Emulsifier to Form Stable Janus Core–Shell Emulsion\nfor Enhancing Agrichemical Delivery

Agrichemical\nlosses are a severe threat to the ecological\nenvironment.\nAdditionally, some agrichemical compounds contain abundant salt,\nwhich increases the instability of formulations, leading to a lower\nagrichemical utilization and soil hardening. Fortunately, the biological\namphiphilic emulsifier sodium deoxycholate alleviates these problems\nby forming stable Janus core–shell emulsions through salinity-driven\ninterfacial self-assembly. According to the interfacial behavior,\ndilational rheology, and molecular dynamics simulations, Janus-emulsion\nmolecules are more closely arranged than traditional-emulsion molecules\nand generate an oil–water interfacial film that transforms\ninto a gel film. In addition, at the same spray volume, the deposition\narea of the Janus emulsion increased by 37.70% compared with that\nof the traditional emulsion. Owing to the topology effect and deformation,\nthe Janus emulsion adheres to rice micropapillae, achieving better\nflush resistance. Meanwhile, based on response of the Janus emulsion\nto stimulation by carbon dioxide (CO₂), the emulsion lost\nto the soil can form a rigid shell for inhibiting the release of pesticides\nand metal ions from harming the soil. The pyraclostrobin release rate\ndecreased by 50.89% at 4 h after the Janus emulsion was exposed to\nCO₂. The Chao1 index of the Janus emulsion was increased\nby 12.49% as compared to coconut oil delivery in soil microbial community.\nThe Janus emulsion ingested by harmful organisms can be effectively\nabsorbed in the intestine to achieve better control effects. This\nstudy provides a simple and effective strategy, which turns waste\ninto treasure, by combining metal ions in agrichemicals with natural\namphiphilic molecules to prepare stable emulsions for enhancing agrichemical\nrainfastness and weakening environmental risk.