Magnetic-Sensitive Nanoparticle Self-Assembled Superhydrophobic Biopolymer-Coated Slow-Release Fertilizer: Fabrication, Enhanced Performance, and Mechanism

Abstract

Although commercialized slow-release fertilizers coated with petrochemical polymers have revolutionarily promoted agricultural production, more research should be devoted to developing superhydrophobic biopolymer coatings with superb slow-release ability from sustainable and ecofriendly biomaterials. To inform the development of the superhydrophobic biopolymer-coated slow-release fertilizers (SBSF), the slow-release mechanism of SBSF needs to be clarified. Here, the SBSF with superior slow-release performance, water tolerance, and good feasibility for large-scale production was self-assembly fabricated using a simple, solvent-free process. The superhydrophobic surfaces of SBSF with uniformly dispersed Fe3O4 superhydrophobic magnetic-sensitive nanoparticles (SMNs) were self-assembly constructed with the spontaneous migration of Fe3O4 SMNs toward the outermost surface of the liquid coating materials (i.e., pig fat based polyol and polymethylene polyphenylene isocyanate in a mass ratio 1.2:1) in a magnetic field during the reaction-curing process. The results revealed that SBSF showed longer slow-release longevity (more than 100 days) than those of unmodified biopolymer-coated slow-release fertilizers and excellent durable properties under various external environment conditions. The governing slow-release mechanism of SBSF was clarified by directly observing the atmosphere cushion on the superhydrophobic biopolymer coating using the synchrotron radiation-based X-ray phase-contrast imaging technique. Liquid water only contacts the top of the bulges of the solid surface (10.9%), and air pockets are trapped underneath the liquid (89.1%). The atmosphere cushion allows the slow diffusion of water vapor into the internal urea core of SBSF, which can decrease the nutrient release and enhance the slow-release ability. This self-assembly synthesis of SBSF through the magnetic interaction provides a strategy to fabricate not only ecofriendly biobased slow-release fertilizers but also other superhydrophobic materials for various applications.

Water Polishing improved controlled-release characteristics and fertilizer efficiency of castor oil-based polyurethane coated diammonium phosphate

“…However, the amount of membrane material he used in the experiment was as high as 9%, leading to high cost, which limited the promotion of CDAP. Several attempts also started with the modification of membrane materials to improve the controlled-release characteristics [25][26][27] . Zhang and Xie prepared superhydrophobic surface with organosilicon modified bio-based polyurethane to prolong the release period of coated fertilizer 25,26 .…”

“…Zhang and Xie prepared superhydrophobic surface with organosilicon modified bio-based polyurethane to prolong the release period of coated fertilizer 25,26 . Xie improved the controlled-release characteristics with magnetic nanomaterials 27 . It is undeniable that their work achieved desired results, yet the synthesis of coating materials were complex and costly.…”

Superhydrophobic Civil Engineering Materials: A Review from Recent Developments

“…Moreover, this coating revealed a transparent superhydrophobicity after being grafted with 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS). Xie et al fabricated superhydrophobic fertilizers via the self-assembly of uniformly dispersed Fe 3 O 4 superhydrophobic nanoparticles on the outermost surface of a mixture [79]. Liu et al synthesized superhydrophobic silica aerogel powders by a phase separation-induced method through the direct hydrophobilization of silica alcogels, which was followed by ambient pressure drying [80].…”

Adhesive Nanocomposite for Prolonging Foliar Retention and Synergistic Weeding and Nourishing

“…[ 4–7 ] Therefore, the demand for increasing the use efficiency of fertilizer and pesticide is growing to solve these problems. [ 8–10 ] Controlled release pesticide‐fertilizer combination (CRPFC), playing a synergistic effect of pesticide and fertilizer, is an effective approach to achieve sustainable circulative agriculture and has garnered considerable attention all over the world. [ 11,12 ]…”