A Comparative Study Of The Conformational Transtitions Of Silk Fibroin Produced By Different Spinning Processes

Rencent years, the regernerated silk fibroin nanofibers are widely used in the biomaterialfield due to its high surface area and excellent biocompatibility. Electrospinning is the mostpopular technique to produce regernerated silk fibroin nanofibers. The diameter of theregernerated silk fibroin nanofibers is usually under100nm, but the poor mechanical propertyand low rate limits its industrialization. Therefore, a new method is need to producedregernerated silk fibroin nanofibers.Centrifugal spinning, a new method, developed in recent years. This paper produced theregernerated silk fibroin nanofibers using the self made centrifugal spinning device, andspecifically to study the effect of concentration, spinneret rotational speed, needle diameter,spinning distance on fiber morphology and diameter.20%concentration,8000rpm spinneretrotational speed,30G needle diameter and12cm spinning distance is the best condition.Mechanical properties of silk fibroin nanofibers is largely determined by the secondarystructure of silk fibroin. To study the effect of electrospinning and centrifugal spinning processon the mechanical properties of regernerated silk fibroin nanofibers, this paper uses scanningelectron microscopy, infrared spectroscopy, X-ray diffraction, far infrared spectroscopy,differential scanning calorimetry thermal analysis, thermal analysis and polarized lightmicroscopy to analysis the surface morphology, structure, thermal performance and degree oforientation. Study the effect of the mechanism of the two spinning process on the surfacemorphology, structure, thermal performance and degree of orientation.Bending instability caused by the electrostatic interactions between the external electricfield and the surface charges occurred in the elongate process. Bending instability isdisadvantage to arrangement and orientation of macromolecular chains along the axial directionof the fiber. Due to the electric field is not required in the centrifugal spinning process, bendinginstability is not exist in the elongate process. Therefore, the macromolecular chains are arranged more regular and order in the centrifugal spinning process. The centrifugal-spun silk fibroin fiberhave more β-sheet conformation, higher crystallinity, better thermal stability and higherorientation, which means better mechanical properties.To quantitative analysis the different of secondary structure of the silk fibroin nanofibers,this paper uses second derivative method to fit the peak at the amide I band of the infrredspectrum. Calculating the rate of random coil, α helix, β sheet and β turn, and analyze the errors.We concluded that the β sheet rate of the silk fibroin nanofibers produced by centrifugal spinningis10%higher than the silk fibroin nanofibers produced by electrospinning, and the relative erroris about10%.