Excellent sustained-release efficacy of herbicide quinclorac with cationic covalent organic frameworks

Ethidium bromide-based covalent organic frameworks (EB-COFs) possess excellent stability and strong adsorption capacities due to their rich cationic charge in the porous structures, making them potential drug release carriers. In this research, EB-COFs nanosheets were prepared for loading and controlling the release of quinclorac (QNC) by mechanical delamination. The loading capacity of QNC into EB-COFs was determined as 41% (w/w). Compared to QNC technical concentrate (TC), the as-obtained stimuli-responsive nanosheets displayed prior controlled-release characteristics. Furthermore, QNC-loaded EB-COFs nanosheets displayed excellent herbicide activities against barnyard grass (Echinochloa crusgalli), when compared to QNC TC. In sum, herbicidal COFs nanosheets look potential as a novel efficient delivery system for pesticide formulations.