Cellulose nanocrystals-reinforced core-shell hydrogels for sustained release of fertilizer and water retention

Core-shell (CS) hydrogels show great potential for the controlled release of fertilizers. In this work, we prepared an alginate-coated gelatin-cellulose nanocrystals (CNCs) hydrogel by a simple layer-by-layer process. CNCs were prepared from cotton linter fibers by the sulfuric acid process. They were incorporated into the gelatin hydrogel, and an external alginate membrane was applied to the inner membrane. Compared to neat gelatin hydrogel, the compressive modulus of the nanocomposite with 5.0 wt% CNCs was enhanced by 288 %. In addition, the CS hydrogel showed a slow-release property and better water retention capacity than neat gelatin hydrogel. The main results of this work are listed below: compression test revealed that the addition of the CNC increases the mechanical properties of the hydrogel, and ii) the addition of a second layer of alginate to CNC-reinforced gelatin hydrogel increase the water retention and improve the sustained release of fertilizer. Our study provides easy and green routes to produce CS hydrogels for potential agricultural applications.