Tailoring Synergistic Multifunctionality in Lightweight Bio‐Inspired Cylindrical Core‐Shell Hybrid Composites.

Biological structures achieve remarkable material performance owing to naturally assembled structures that extend from the molecular to macro‐scale. Synergy among constituents of various length scales yields lightweight, hierarchically structured materials with properties superior to those of individual components. To replicate nature's ingenuity, this work emulates the cylindrical core‐shell structure found in osteons and bamboo, utilizing Halloysite Nanotubes (HNTs) and Glass Fibers (GFs) in a semi‐crystalline polymer matrix. HNTs are environmentally friendly, naturally occurring tubular aluminosilicates with high aspect ratios, large lumen volumes, and low cost, and are readily dispersible in polymer matrices. Here, hierarchical reinforcement is achieved through controlled electrostatic assembly of HNTs onto GFs and subsequent trans‐crystallization‐encapsulation. This cylindrical core‐shell architecture yields composites with exceptional mechanical performance, superior thermal management (insulation/stability), improved industrial processability, and reduced flame propagation speed. Compared to the current industrial composite substitute for metallic structural components, the hybrid composites exhibit a remarkable 84% increase in impact strength, 27% increase in specific tensile strength, 56% increase in tensile toughness, and 30% in specific flexural strength, accompanied by a 20% weight reduction and a 255% increase in processability (melt‐flow index). This scalable assembly strategy marks a cornerstone in lightweight multifunctional materials development, to conquer future sustainability targets. [ABSTRACT FROM AUTHOR]