Smart Fertilizer With Temperature-Responsive Behavior Coated Using a Naturally Derived Material

The development of temperature-responsive coated urea from sustainable, environmentally friendly bio-coatings has garnered increasing research attention owing to concerns regarding global food security and environmental sustainability. In this study, naturally derived coated urea with temperature-responsive behavior (SNCU) was fabricated using castor oil/polycaprolactone (PCL2000) blends and isocyanate, nano-SiO 2 and siloxane were employed to enhance its hydrophobicity. Nutrient (N)-release experiments were conducted at various temperatures to explore the temperature-responsive behavior of the coated urea. The temperature-response mechanism and composition of the coated urea were investigated using x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), simultaneous thermal analysis (DSC), and Fourier-transform infrared (FT-IR) spectroscopy. Results indicated that PCL2000 incorporation could produce a block polymer with a two-phase structure consisting of a crystalline and an amorphous phase, and the SNCU exhibited a significant temperature switch at 32.5°C. Moreover, the N-release SNCU longevity increased to 70 days. Therefore, the findings from this work highlight that temperature-responsive SNCU, with its higher N availability, could be suitable for agricultural applications in sustainable, green agricultural development.