Electrospun nanofiber mats from aqueous starch-pullulan dispersions: Optimizing dispersion properties for electrospinning.

A green method to fabricate starch-based nanofibers is provided. High-temperature (≈162 °C) was used to destructure high-amylose starch in water. Sodium palmitate was added to enhance the stability of high-amylose starch in water at room temperature and increase the conductivity of the electrospinning dope. Flow properties and zeta potential of starch-palmitate dispersions were characterized by rheometer and dynamic light scattering, respectively. Pullulan was mixed in as a minor component of the starch-palmitate complex (starch:pullulan at a ca. 2:1 ratio) and the mixture electrospun. Pullulan hindered starch association and modified the dispersion properties, promoting molecular entanglement without gelation. The presence of sodium palmitate-starch inclusion complexes in the fiber was confirmed by differential scanning calorimetry and X-ray diffraction. Tensile strength of the nanofiber composite was found to be weaker than that of micro-sized pure starch fiber mats. This method provides future industry with lower cost by eliminating the use of organic chemicals.