title: Structural characteristics and properties of the regenerated silk fibroin prepared from formic acid.
abstract: Structural characteristics and thermal and solution properties of the regenerated silk fibroin (SF) prepared from formic acid (FU) were compared with those of SF from water (AU). According to the turbidity and shear viscosity measurement, SF formic acid solution was stable and transparent, no molecular aggregations occurred. The sample FU exhibited the beta-sheet structure, while AU random coil conformation using Fourier transform infrared (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry. The effects of methanol treatment on samples were also examined. According to the measurement of crystallinity (XRD) and crystallinity index (FTIR), the concept of long/short-range ordered structure formation was proposed. Long-range ordered crystallites are predominantly formed for methanol treated SF film while SF film cast from formic acid favors the formation of short-range ordered structure. The relaxation temperatures of SF films measured by dynamic thermomechanical analysis supported the above mechanism due to the sensitivity of relaxation temperature on the short-range order.
authors.affiliation: Department of Natural Fiber Sciences, College of Agriculture and Life Sciences, Seoul National University, Suwon 441-744, South Korea.
authors.forename: I C
authors.initials: IC
authors.lastname: Um
authors.forename: H Y
authors.initials: HY
authors.lastname: Kweon
authors.forename: Y H
authors.initials: YH
authors.lastname: Park
authors.forename: S
authors.initials: S
authors.lastname: Hudson
mesh_terms: D000818:Animals; D012831:Bombyx / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D003460:Crystallization; D005349:Fibroins / Q000737:chemistry* / Q000302:isolation & purification; D005561:Formates; D019476:Insect Proteins / Q000737:chemistry* / Q000302:isolation & purification; D046911:Macromolecular Substances; D015394:Molecular Structure; D009391:Nephelometry and Turbidimetry; D017433:Protein Structure, Secondary; D012212:Rheology; D047011:Silk; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014783:Viscosity; D014867:Water; D014961:X-Ray Diffraction
chemical_list: D005561:Formates; D019476:Insect Proteins; D046911:Macromolecular Substances; D047011:Silk; D012996:Solutions; D014867:Water; C030544:formic acid; D005349:Fibroins