Current composites for the military (e.g. carbon fibers) are typically derived from polyacrylonitrile (PAN) polymer fibers. Synthesis utilizes toxic chemicals, volatile organic solvents and extremely high temperatures. This project addresses these shortcomings by replacing toxic materials with protein nanotubes/nanofibrils generated from waste materials and utilizing aqueous based fiber spinning to eliminate the need for hazardous processes. This project specifically explored the feasibility of spinning protein nanotubes into fibers and initiated characterization of the properties of such fibers.
Researchers focused on the generation of protein nanotubes from waste materials for use in various bionanotechnologies. Inspired by the synthesis routes and properties of natural fibers, the researchers used liquid crystalline solutions of structural proteins and rod-shaped bacterial viruses as precursors to fabricate functional fibers. This Limited Scope effort has enabled the researchers to merge these existing capabilities and explore the feasibility of preparing military relevant fibers from renewable waste protein materials (e.g. eye lenses proteins).
A systematic evaluation of aqueous based wet-spin processing parameters necessary for the generation of protein based fibers was conducted. Characterization of molecular alignment was conducted using optical microscopy and qualitative properties of the fibers was determined. In addition, conditions were defined for the control of nanofibril structure enabling the formation of extended nanofibrils (to several microns), highly branched nanofibril networks, or bundled nanofibrils.
The availability of fibers that can be spun or assembled at high concentrations from sustainable resources and environmentally friendly processes, and in which the fibers themselves have structural integrity provide the potential for multi-functionality. A broad range of military relevant applications are possible such as higher-strength bioplastics and nanocomposites, water-repelling coatings, textiles, immobilized catalysts, surface-active packaging, enzyme reactors, decontamination of chemical and biological warfare agents, bioremediation, and even electronics.