Characterization of Regenerated Silk Material for Biomimetic Spinning and Film Casting

Abstract

Natural silks produced by spiders and silkworms exhibit tailorable mechanical performance yet to be achieved synthetically. This phenomenon is derived from a biological system that has been evolutionarily optimized. In efforts to harness this elusive promise of tailorable bio-material fabrication, a study was conducted to investigate: 1) silk solution processing, 2) silk spinning via a biomimetic spinning system, [and] 3) dispersions of carbon nanotubes into regenerated silk by spinning and casting. A formic acid calcium chloride solvent system was chosen by rheological characterization for further processing. Fibers were spun through the biomimetic system using hydrodynamic fluid focusing (HF) yielding predictable diameters, with improved mechanical performance correlated to smaller diameter fibers resulted from HF. Alternatively, carbon nanotubes functionalized with carboxylic-acid (CNTC) and non-functionalized (CNTNF) were integrated into spinning and casting processes. Decreases in performance was observed in CNTNF constructs, however an increase was present in CNTC suggesting structural integration of silk proteins.