Honokiol‐based pH ‐responsive amphiphilic polymer as an intelligent delivery system for rhizosphere‐targeted herbicide application

Abstract BACKGROUND The development of efficient and environmentally friendly herbicide‐delivery systems is crucial in modern agriculture. Such systems can achieve precise targeting and controlled release of active ingredients through formulation technologies like slow‐release carriers and targeted microcapsules. This study aims to synthesize a novel bio‐based polymer through polycondensation of the natural product honokiol with triethylene glycol divinyl ether, and to evaluate its potential as a herbicide carrier. RESULTS This study successfully synthesized an amphiphilic honokiol‐based polymer. The resulting polymer micelle suspension, formed via self‐assembly, exhibited a particle size of 130.5 nm, a critical micelle concentration of 3.8 × 10 −3 mg/mL, a drug loading capacity of 13.79%, and an encapsulation efficiency of 82.75%. In vitro release studies demonstrated pH‐dependent kinetics, with 80.1% cumulative release of diuron at pH 5.0 over 60 h, compared with only 16.35% at pH 7.0. Herbicidal activity tests against Echinochloa crus‐galli demonstrated that the polymer micelle suspension achieved higher mortality rates and fresh weight reduction than diuron dispersion systems, attributable to their rhizosphere‐triggered release properties, while significantly enhancing crop seedling safety. CONCLUSIONS This study represents the first successful application of honokiol‐based polymers in the field of herbicide delivery. The carrier system exhibits excellent controlled‐release properties and synergistic effects, significantly enhancing herbicide utilization efficiency while reducing potential environmental risks. These findings provide a promising strategy and material foundation for developing a new generation of green pesticide formulations. © 2025 Society of Chemical Industry.