Fabrication of a dual pH‐responsive and photothermal microcapsule pesticide delivery system for controlled release of pesticides

BACKGROUND The development of stimulus‐responsive and photothermally controlled‐release microcapsule pesticide delivery systems is a promising solution to enhance the effective utilization and minimize the excessive use of pesticides in agriculture. RESULTS In this study, an AVM@CS@TA‐Fe microcapsule pesticide delivery system was developed using avermectin as the model drug, chitosan and tannic acid as the wall materials, and tannic acid–Fe complex layer as the photothermal agent. The optical microscope, scanning electron microscope, transmission electron microscope, and Fourier‐transform infrared spectroscope were used to characterize the prepared microcapsule. The slow‐release, UV‐shielding, photothermal performance, and nematicidal activity of the microcapsule were systematically investigated. The results showed that the system exhibited excellent pH‐responsive and photothermal‐sensitive performances. In addition, the UV‐shielding performance of the delivery system was improved. The photothermal conversion efficiency (η) of the system under the irradiation of near‐infrared (NIR) light was determined to be 14.18%. Moreover, the nematicidal activities of the system against pine wood nematode and Aphelenchoides besseyi were greatly increased under the irradiation of light‐emitting diode (LED) simulated sunlight. CONCLUSION The release of the pesticide‐active substances in such a pesticide delivery system could be effectively regulated with the irradiation of NIR light or LED‐simulated sunlight. Thus, the developed pesticide delivery system may have broad application prospects in modern agriculture fields. © 2022 Society of Chemical Industry. The AVM@CS@TA‐Fe microcapsule system exhibited excellent pH‐responsive and photothermal performances. The release of pesticides in the system could be effectively regulated with the irradiation of near‐infrared light or light‐emitting diode‐simulated sunlight.