Multicompartment micelles (MCMs), whose cores have at least two compartments, show potential applications in various areas, but the synthesis of polymers for preparing MCMs is usually tedious and time-consuming. In this work, two well-defined telechelic fluorocarbon-terminated triblock copolymers, F 8 -PEO 100 -PPO 65 -PEO 100 -F 8 (F 8 -F127-F 8 ) and F 8 -PEO 132 -PPO 50 -PEO 132 -F 8 (F 8 -F108-F 8 ), are synthesized via a single-step coupling reaction of Pluronics F127 or F108 with perfluoro-1-octanesulfonyl fluoride and characterized by Fourier-transform infrared and NMR spectroscopies, as well as gel permeation chromatography and surface tensiometry. Both of these fluorocarbon-terminated Pluronics can self-assemble into spherical MCMs with Janus-core in aqueous solution, as evidenced by transmission electron microscopy imaging. Since the lipophilic block (PPO) and fluorophilic segments (F 8 ) are separated by the hydrophilic blocks (PEO), these fluorocarbon-terminated Pluronics will loop to give rise to flower-like MCMs, and the calculations based on thermodynamics and dynamics support the formation of such unique aggregates. A “pre-self-assembly” mechanism is proposed to explain the formation process of flower-like MCMs with Janus-core prepared by these telechelic fluorocarbon-terminated triblock copolymers.
Agrichemical losses are a severe threat to the ecological environment. Additionally, some agrichemical compounds contain abundant salt, which increases the instability of formulations, leading to a lower agrichemical utilization and soil hardening. Fortunately, the biological amphiphilic emulsifier sodium deoxycholate alleviates these problems by forming stable Janus core–shell emulsions through salinity-driven interfacial self-assembly. According to the interfacial behavior, dilational rheology, and molecular dynamics simulations, Janus-emulsion molecules are more closely arranged than traditional-emulsion molecules and generate an oil–water interfacial film that transforms into a gel film. In addition, at the same spray volume, the deposition area of the Janus emulsion increased by 37.70% compared with that of the traditional emulsion. Owing to the topology effect and deformation, the Janus emulsion adheres to rice micropapillae, achieving better flush resistance. Meanwhile, based on response of the Janus emulsion to stimulation by carbon dioxide (CO2), the emulsion lost to the soil can form a rigid shell for inhibiting the release of pesticides and metal ions from harming the soil. The pyraclostrobin release rate decreased by 50.89% at 4 h after the Janus emulsion was exposed to CO2. The Chao1 index of the Janus emulsion was increased by 12.49% as compared to coconut oil delivery in soil microbial community. The Janus emulsion ingested by harmful organisms can be effectively absorbed in the intestine to achieve better control effects. This study provides a simple and effective strategy, which turns waste into treasure, by combining metal ions in agrichemicals with natural amphiphilic molecules to prepare stable emulsions for enhancing agrichemical rainfastness and weakening environmental risk.
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