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

Abstract

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.