Tailored hydrogel properties through blending homopolymer celluloses: A novel approach for sustainable biomaterials

Abstract

The growing reliance on synthetic polymers for hydrogel production underscores the urgent need to explore natural polymers, particularly cellulose. However, molecular weight (MW) of cellulose, depending on its source significantly affects the hydrogel’s physicochemical properties. Here, we report a simple yet compelling strategy to fine-tune the physicochemical properties of the hydrogel by blending cellulose of varying MWs. High and low MW celluloses were extracted from pineapple leaf fiber (PALF) and Orthosiphon aristatus stem fiber (OASF) through chemical pre-treatments, then blended in varying ratios, dissolved in N, N-dimethylacetamide/lithium chloride, and regenerated in an ethanol-vapor environment to form PALF/OASF hydrogels. Blending high-MW PALF with low-MW OASF cellulose produced hydrogels with distinct physicochemical properties. Pure PALF (PALF100-OASF0) exhibited the highest viscosity (303 cP), gel fraction (33.26 %), crystallinity (52.6 %), Young's modulus (1.12 MPa), and cohesiveness (2.2 g·s), indicating strong polymer interactions and chain entanglement. In contrast, pure low-MW OASF (PALF0-OASF100) showed the lowest values. Blending high-MW PALF with low-MW OASF reduced these properties while increasing the equilibrium swelling ratio and mesh size, enhancing hydrogel flexibility for biomaterial applications. The antibacterial property of hydrogel is improved by loading tannic acid and exhibited antibacterial activity against E. coli. This study highlights the transformative potential of valorizing agricultural waste into cellulose-blend hydrogels, promoting a circular economy. By integrating sustainability into material science, these bio-based hydrogels offer a promising pathway for future innovations in waste management and advanced biomaterials, paving the way for eco-conscious solutions in various industries.