Functional Cross-Linked Electrospun Polyvinyl Alcohol Membranes and Their Potential Applications

Polyvinyl alcohol (PVA) is a water soluble polymer that requires further treatment to be stabilized before it can be used in aqueous environments. Electrospun PVA is cross-linked by incorporating cross-linking agents directly into the electrospinning solution followed by post-electrospinning thermal treatments to attain stability in aqueous environments. Previously published works on post-treatments include glutaraldehyde vapor exposure or soaking in organic solvents such as ethanol. However, these treatments incur lots of difficulties and hazards especially in scale production. In this study, with a view of imminent scale-up production required, fabricating electrospun cross-linked PVA is investigated without using catalysts, toxic vapor exposure, or solvent treatment. To produce cross-linked electrospun PVA membranes, citric acid, maleic acid, and polyacrylic acid are, respectively, added to PVA solution prior to electrospinning. Two potential applications are examined; the first is to use the membranes as produced for metal uptake in aqueous systems. The second application is for ammonia adsorption after decorating the membranes with a metal organic framework, copper benzene-1,3,5-tricarboxylate (HKUST-1).