Structural characterization and mechanical properties of electrospun silk fibroin nanofiber mats

The regenerated silk fibroin dissolved in formic acid was electrospun into nanofiber mats. Structural characteristics of the spun as received and methanol and ethanol treated fibers were examined using the Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction. Mechanical properties and air permeability of the electrospun mats were also studied. IR spectroscopy and X-ray diffractometry showed random coil conformation and amorphous structure for as-spun fibers while typical FTIR spectra and X-ray diffractograms of β-sheet crystalline structure were recorded for the methanol and ethanol treated fibers. The mechanical properties of the mats were found to be dependent on fiber diameter. The mats containing fibers with smaller diameter had higher tensile strength but lower breaking strain. Methanol and ethanol treatment enhanced tensile strengths of the mats at the expenses of their breaking strain. Air permeability and pore size of the mats are strongly associated with diameter of the electrospun fibers

Electrospinning of silk nanofibers. I. An investigation of nanofiber morphology and process optimization using response surface methodology

Ultra fine fibers were electrospun from regenerated silk fibroin/formic acid solution. Effect of some process parameters on the morphology, diameter and variation in fiber diameter of electrospun fibers were experimentally investigated. Scanning electron microscope was used for the measurement of fiber diameter. Fibers with diameter ranging from 80 to 210 nm were collected depending on the solution concentration and the applied voltages. Response surface methodology (RSM) was used to obtain a quantitative relationship between selected electrospinning parameters and the average fiber diameters and its distribution. It was shown that concentration of silk fibroin solution had a significant effect on the fiber diameter and the standard deviation of the fiber diameter. Applied voltage had no significant effect on the fiber diameter and its standard deviation

Effects of some electrospinning parameters on morphology of Natural silk-based nanofibers

Natural silk, from Bombyx mori solutions were electrospun into nanofibers, with diameters ranged from 60 to 7000 nm. The effects of electrospinning temperature, solution concentration and electric field on the formation nanofibers were studied. Optical and scanning electron microscope were used to study the morphology and diameter of electrospun nanofibers. It was observed that the nanofibers became flattened with ribbon-like shape with increasing the electrospinning temperature. The nanofiber diameter increases with the increase in the concentration of silk solution at all electrospinning temperature. With increasing the voltage of electric field at 50°C, morphology of the nanofibers changes from ribbon-like structure to circular cross section. Referring to the literature the probable mechanism responsible for the change of morphology is pointed out