The Stability of Chlorite Ion in Electrospun Poly(Vinyl Alcohol) Fibers: pH-Responsive Chlorine Dioxide Release

Poly-(vinyl alcohol) (PVA)-based electrospun fiber mats containing sodium chlorite were prepared and characterized to explore their structural properties and chemical behavior relevant to potential self-disinfecting wound dressing applications. Scanning electron microscopy (SEM) revealed that the diameter and uniformity of the fibers are influenced by both the chlorite ion concentration and the pH of the spinning solution. Elemental mapping and ion chromatography confirmed the homogeneous distribution of chlorite ions within the mats. The decomposition of the chlorite ion was found to be pH-dependent, with enhanced stability at alkaline pH and lower chlorite concentrations. At acidic pH, chlorite rapidly decomposes, primarily forming chlorine dioxide, which is a desirable disinfectant. Higher chlorite ion concentrations favor the formation of an unwanted chlorate ion. Gas chromatography confirmed the evolution of ClO₂ over extended time, and ¹H NMR analysis verified that side reactions with the PVA matrix contribute to chlorite ion depletion. The system's response to skin-like pH conditions demonstrated relatively fast ClO₂ release, underlining the importance of local environmental factors. Overall, low chlorite ion concentrations and a slightly basic pH are required to produce stable mats. The functional electrospun PVA mats presented here are promising candidates for controlled antimicrobial release of ClO₂ in biomedical applications.