Asymmetric Wetting Janus Mesoporous Silica Nanopesticide Delivery System with Enhanced Foliar Deposition Ability and Sustained-Release Behavior for Increasing Pesticide Utilization Efficiency

Mitigating inefficiencies and environmental pollution caused by weak foliar adhesion and rapid release during pesticide application is a significant challenge in agricultural development. This study addresses this issue by preparing asymmetric wetting Janus mesoporous silica nanocarriers (AWJ-MSN) through the adjustment of hydrophilic and hydrophobic monomer ratios via interfacial modification. Subsequently, asymmetric wetting Janus nanopesticide delivery systems (Thi@AWJ-MSN) were constructed by encapsulating the model pesticide molecule, thiafuramide (Thi). The coexistence of hydrophilic and hydrophobic segments on the AWJ-MSN imparts interfacial activity, enhancing spreadability on plant leaves with different wettability (Brassica chinensis L., Cucumis sativus L., and Arachis hypogaea L.). The droplet impact behavior of the AWJ-MSN on plant leaves and artificial PTFE membrane surfaces was analyzed through normalization, revealing a reduced normalized spreading height (H_t/D₀) and an increased normalized spreading diameter (D_t/D₀). These findings indicate the enhanced foliar deposition ability of the AWJ-MSN under real-world foliar spraying conditions. Furthermore, the encapsulation of Thi within the nanocarriers protects the active pesticide ingredients, enabling sustained release through quasi-Fickian diffusion and ultimately prolonging the pesticide’s efficacy. This study provides theoretical guidance for the aqueous formulation and reduction of pesticide use, contributing to reduced environmental risks and offering potential applications in agriculture.