Preparation, characterization and antimicrobial activity of sodium carboxymethyl cellulose - based hydrogels by freeze-thaw method

This study evaluated the structural and functional properties of poly (vinyl alcohol)/sodium carboxymethyl cellulose (PVA/NaCMC) hydrogels synthesized via the freeze-thawing method using 1% acetic acid (AAc) and distilled water (Dw) as solvents. The results demonstrate that solvent choice and NaCMC concentration significantly influence hydrogel performance, particularly for wound dressings. PVA/NaCMC (AAc)-3.5% emerged as the optimal formulation, exhibiting superior antimicrobial activity, structural stability, and enhanced crosslinking, as evidenced by FT-IR, SEM, and TEM analyses. XRD confirmed higher crystallinity in the AAc-based hydrogel, while swelling tests showed greater water absorption in the Dw-based hydrogel, attributed to its looser network. Antimicrobial tests highlighted the broad-spectrum efficacy of PVA/NaCMC (AAc)-3.5%, inhibiting Gram-positive and Gram-negative bacteria and fungi due to acetic acid's low pH and hydrogen bond stabilization. These findings emphasize the importance of solvent selection in designing hydrogels for wound care applications requiring infection prevention and structural integrity.