Biocompatible CMC-based hydrogel fiber systems: swelling control via trivalent ionic crosslinking

Carboxymethyl cellulose (CMC) is a hydrophilic and biocompatible polysaccharide widely employed in hydrogel systems. Herein, CMC-based fibers were ionically crosslinked using different trivalent cations, Al³⁺, Ce³⁺, and Fe³⁺, to investigate the effects of crosslinking type on water swelling behavior and surface morphology. Swelling studies were conducted in distilled water at room temperature, and the water uptake of each crosslinked sample was evaluated over time. The results showed that Al³⁺-CMC fibers had the highest swelling ratio, whereas Fe³⁺-treated fibers demonstrated more limited swelling due to their denser network structure. Ce³⁺-CMC fibers displayed intermediate behavior. Linear density analysis showed an increasing Tex trend from Al³⁺- to Ce³⁺- and Fe³⁺-crosslinked fibers, consistent with their respective swelling behaviors and morphological characteristics. To further understand the influence of crosslinking, fiber morphology was analyzed using scanning electron microscopy. The images revealed distinct differences in surface features, with Al³⁺-treated samples showing more pronounced surface roughness, while Fe³⁺-CMC fibers were smoother and more compact. These findings suggest that the choice of trivalent crosslinker significantly influences both the swelling characteristics and morphology of CMC fibers. The tunable properties of these ionically crosslinked fibers indicate their potential suitability for various applications such as controlled release systems, wound dressings, and biodegradable packaging materials.