Effect of nonionic surfactant and acidity on chitosan nanofibers with different molecular weights

Blend solutions of chitosan (Cs) and poly(ethylene oxide) (PEO) at different acidities were electrospun to produce membranes of nanofibers with different diameters. The use of polysorbate surfactant Tween 20 to improve functionality of these nanofibers was studied. The procedure was as follows: 5% (w/v) of two high deacetylation degree Cs with different molecular weights (Mw = 148 kDa and 68 kDa) were dissolved in solutions with different acetic acid concentrations (10%, 50% and 90% (v/v)) then mixed with PEO. The influence of molecular weight and acidity on the morphology and physicochemical properties of solutions and formed nanofibers was also investigated. Results revealed that pure Cs dissolved in different acidities did not form fibers and instead it deposited as beads. Addition of PEO was necessary to electrospin all Cs solutions. Average fiber diameters and size distribution differ with acidity and molecular weight. Composite solutions of Cs, synthetic polymer PEO, and surfactant can be effectively electrospun. The presence of surfactant resulted in decrease of surface tension and in the formation of smooth or beaded fibers. This may be important for new applications since active nanofibers could serve as carriers of components such as drugs or additives.