A series of pH-sensitive electrospun nanofibers based on Eudragit/chitosan blend with modulated properties for...

Eudragit nanofibers are smart and pH-sensitive materials that experience extensive structural changes with pH variations. In the present study, a new solvent system was developed for electrospinning of Eudragit and the physicochemical properties of the resulting nanofibers were compared with those produced from conventional solvents used for electrospinning. Electrospinning with an acidic mixed solvent produced fibers with minimal structural and dimensional changes at both acidic and neutral pH and enabled the combination of a natural polymer, chitosan, with Eudragit. Then, chitosan was added to Eudragit and Eudragit/chitosan blended nanofibers with different blending ratios were prepared. Chemical, morphological, thermal and mechanical properties of the fibers, as well as their stability in aqueous media, were evaluated by various analyses. Morphological evaluation showed that increasing chitosan ratio in blended nanofibers decreased the fiber diameter. Shrinkage measurement revealed that increasing chitosan ratio did not significantly change the structural and dimensional stability of the fibers, however, morphological observation following shrinkage measurement corroborated the better stability of the fibers with 10% chitosan ratio at both acidic and neutral pH. Swelling and contact angle measurements verified that bulk and surface hydrophilicity increased proportionally with the chitosan ratio. Mechanical assay confirmed that nanofibers with 10% chitosan had higher strength and modulus compared to other formulations. Therefore, it can be said that fibers with 10% chitosan have better wettability and mechanical properties, while experiencing less structural changes and shrinkage than pure Eudragit fibers, and are considered an ideal choice as a pH-sensitive material.