Adaptive Droplet-Foliar Pinning and Topological Interlocking Synergistically Enhance Nanoagrochemical Delivery

The performance of nanoagrochemicals at nanobiointerfaces is limited by insufficient adhesion, especially on superhydrophobic leaves. Herein, we propose a paradigm to enhance foliar delivery via the synergistic optimization of pinning and topological interlocking effects. We designed spiny pollen-like silica, loaded with ammonium chloride, and synergistically incorporated 0.2 wt % sodium dodecylbenzenesulfonate (SDBS) to construct a composite fertilizer system designated PSN0.2. The system switched droplets from the nonwetting Cassie-Baxter state (contact angle >120°) to the high-adhesion Wenzel state (contact angle ≈ 50.2°), enabling adaptive penetration into leaf microstructures, enhancing pinning-induced interfacial adhesion, and suppressing droplet bouncing. Compared with traditional foliar nitrogen fertilizer (TFNF), PSN0.2 increased nitrogen retention on rice (Oryza sativa L.) leaves by 234% after application and 547% after simulated rainfall washing, demonstrating excellent rainfastness. Additionally, PSN0.2 enabled the uniform distribution of silica across leaf surfaces and enhanced adhesion through topological interlocking. Pot experiments showed PSN0.2 increased the dry biomass of nitrogen-deficient rice seedlings by 80% relative to TFNF. Field experiments demonstrated PSN0.2 increased rice yield by 17.5% over traditional fertilization practice (TFP), despite 10% less nitrogen input. This work provides a simple and effective approach for developing foliar fertilizers with strong adhesion and excellent rainfastness, advancing sustainable agriculture.