One-step synthesis of superhydrophobic and multifunctional nano copper-modified bio-polyurethane for controlled-release fertilizers with multilayer air shields: new insight of improvement mechanism

Recently, superhydrophobic bio-based coating materials for sustainable and environmentally friendly controlled-release fertilizers (CRFs) have drawn much attention. The synthesis procedure of superhydrophobic nanomaterials have developed rapidly, but their applications in coating for superhydrophobic CRFs are still limited to small-scale uses because of the heavy environmental concerns and economic expenses. In this study, a novel one-step process was developed to synthesize nano lauric acid copper using ethyl alcohol and water as solvents. This nanomaterial was not only successfully used to modify bio-polyurethane, derived from castor oil for coating urea fertilizer to improve its release characteristic, but also was coated on different substrates including paper, metal, glass, and non-woven fabrics to make their surfaces superhydrophobic and superoleophilic. Non-woven fabrics and a 100 mesh nylon net coated with this nanomaterials effectively separated crude oil-in water emulsion with an ultrahigh efficiency and reusability. Furthermore, the nanomaterial exhibited excellent antibacterial properties and long-term stability. Overall, this novel nano lauric acid copper is a cost-effective and multifunctional coating material that has many promising applications, including controlled-release and oil/water separation in the future.