Functionalized halloysite nanotubes as chlorpyrifos carriers with high adhesion and temperature response for controlling of beet armyworm

Intelligent responsive pesticide delivery systems have been used in agricultural applications to improve pesticide utilization. To improve the bioavailability of pesticides for combating the growth of beet armyworm (which grows fastest at 35°C), we constructed a halloysite nanotubes (Hal)-based sustained release system with intelligent temperature-responsive release properties and strong adhesion to leaves. Hal, N-isopropylacrylamide (NIPAm), dopamine (DA, polydopamine is abbreviated as PDA) and chlorpyrifos (CPF) were used as the raw materials to prepare (PNIPAm-g-Hal)@CPF@PDA (PHCP). PHCP had excellent thermosensitive release performance, and the average release rate at 35°C was approximately 2.5 times higher than that at 25°C. Through a simulated rainwater scour experiment, the retention rate of PHCP on corn leaves was 83.52% (2.25 times higher than that of (PNIPAm-g-Hal)@CPF) (PHC). The continuous release time of CPF from PHCP was more than 60 h. PHCP improved the UV-shielding performance of CPF, and it took 12 times longer than the original CPF to reach the same degradation rate. This study demonstrates a strategy to design pesticide carriers according to the characteristics of the target, which is widely applicable to protect crops, improve the utilization rate of pesticides, and protect the environment.