Honokiol-based pH-responsive amphiphilic polymer as an intelligent delivery system for rhizosphere-targeted herbicide...

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.

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.

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.