Vine-inspired 3D self-supporting spiral networks enable all-polymer composites advanced dielectric properties and isotropic thermal management

Traditionally, it has been considered impossible to overcome the directional limitations associated with polarization and thermal conductivity (λ) in laminated all-polymer composites, which are essential for signal transmission and heat dissipation in fifth-generation equipment shells. Herein, by utilizing hierarchical weaving technology, a vine-like three-dimensional (3D) ultrahigh molecular weight polyethylene (UHMWPE) spiral network is created in laminated ramie-reinforced composites. This unique spiral structure ensures polarization balance by continuously dispersing functional UHMWPE crystals in multiple directions, and it safeguards the micro/nanopores (air carriers) of ramie through self-support, thereby achieving exceptional microwave transmittance (98.3 %). Remarkably, this structure effectively overcomes the limitations of thermal paths in laminated composites along their vertical plane directions, thus simultaneously obtaining high in-plane λ (3.3354 W/mK) and through-plane λ (3.2756 W/mK). This novel approach based on a functional crystal-based 3D spiral network challenges the stereotypes regarding all-polymer composites, particularly in terms of advanced dielectric properties and isotropic thermal management.