(398br) Mimicking Nature: Mechanical Properties of Ultrastretchable, Silica-Based Synthetic Spider Webs Fabricated Via 3D Printing
By reacting polyurethane with i) ethylene glycol, ii) hydroquinone, and iii) fumed silica particles, we have synthesized three types of polymers with varying tensile properties. We have quantified the glass transition temperature and rheological properties of the polymers. Both films and fibers prepared with polyurethane-silica composites were highly stretchable, with an average strain above ~4000 % at break of the fibers. We propose that these tensile properties originate from the covalent and non-covalent 3D crosslink system between the elastic polymer and rigid silica domains. The polyurethane-silica composite was cast into films, wet spun into fibers and used as an ink for 3D printing at room temperature using a customized 3-dimensional pneumatic dispensing robot. We 3D printed grids and spider-webs with increasing number of interconnected junctions, relating mechanical properties to the architecture. This in depth understanding of the structural-functional-property relationship of elastic nets will enable future design of complex structures, requiring advanced functional materials for high tech applications.