PAN Fiber Electrospinning with Polyazide Cross-Linking for Toughness

The patent applies preliminary action by incorporating polyazide compounds into the PAN solution before electrospinning. These compounds undergo cross-linking reactions during or after fiber formation, creating a pre-established network structure that enhances mechanical properties. The cross-linking agents are introduced in advance into the spinning solution, allowing the hierarchical structure to develop during the electrospinning process itself, rather than requiring complex post-processing steps.

The patent creates composite materials by combining PAN with polyazide compounds (such as poly(ethylene glycol) bisazide or polyurethane bisazide). This composite approach allows the PAN fibers to benefit from the cross-linking network formed by the polyazide, resulting in enhanced toughness and tensile strength. The composite structure mimics the hierarchical organization found in natural spider silk, where different components work together to achieve superior mechanical performance.

The patent applies segmentation by creating a hierarchical structure where nanofibers are bundled into macrofibers, which are then organized into yarns. This multi-level segmentation mirrors the structure of natural spider silk, where nanoscale crystallites are arranged in hierarchical patterns. The cross-linking network is established at multiple scales, with polyazide compounds forming bonds between individual nanofibers and between bundles, ensuring structural stability throughout the hierarchy.

The patent implements the nested doll principle by organizing fibers at multiple scales: nanofibers are nested within macrofiber bundles, which are nested within yarn structures. Each hierarchical level contains and is contained by the next level, creating a nested architecture similar to natural silk. The cross-linking network is established at each nested level, with polyazide compounds forming connections between nanofibers within macrofibers and between macrofiber bundles within yarns, ensuring stability throughout the nested hierarchy.