Haichao Cao,Yue Chen,Zhigang Qian,Tingjie Huang,Nan Zou,Daxia Zhang,Wei Mu,Beixing Li,Feng Liu
The foliar loss of pesticides causes serious utilization decline and environmental risk. On the basis of biomimetics, pesticide-loaded microcapsules (MCs) with spontaneous deformation on foliar micro/nanostructures, like the snail suction cup, are prepared by interfacial polymerization. By controlling the usage or types of small alcohols in the MC preparation system, the flexibility of MCs is tunable. Through the investigation of emulsions and MC structures, we discover that the migration and distribution of small alcohols driven by amphiphilicity affect the process of interfacial polymerization between polyethylene glycol and 4,4-methylenediphenyl diisocyanate. By hydrophobic modification of the polymer and competition for oil monomers of small alcohols, the thickness and compactness of shells are reduced, whereas the density of the core is increased. As a result of the regulation in structures, the flexibility of MCs is improved significantly. In particularly, the MCs-N-pentanol (0.1 mol kg–1) with the best flexibility show strong scouring resistance on varied foliar structures, sustained release property on the air/solid interface, and persistent control effect against foliar diseases. The pesticide-loaded soft MCs provide an effective way to improve pesticide foliar utilization.
Broadband solar light absorption and visible light photocatalysis of surface modified ultrawide bandgap semiconductors are receiving wide attentions because of their more negative conduction band potential and positive valence band potential for refractory organics degradation. Here, we reported a novel modified solvothermal strategy by the introduction of distilled water into small molecular alcohols to synthesize crystallized carbon-coated Zr 3+ -ZrO 2 composites for enhanced visible light absorption and visible light photocatalytic tetracycline degradation, in which the distilled water favored for the crystallization of Zr 3+ -ZrO 2 and the formed ultrathin carbon layers derived from the polymerization of small molecular alcohols were contributing to the generation of Zr 3+ species and well dispersion of Zr 3+ self-doped ZrO 2 nanoparticles. The experimental results also showed that carbon-coated Zr 3+ -ZrO 2 composites exhibited enhanced visible light absorption, long-lived charges, efficient visible light photocatalytic performance and good recyclable stability. Besides, possible photocatalytic mechanism and antibiotic degradation pathways over carbon-coated Zr 3+ -ZrO 2 composites under visible light irradiation were also proposed in detail.