Metal‐Free Submicron‐Hollow‐Fiber Conjugated Polymer Sponges for Efficient Pollutant Removal and Thermal Insulation

Inspired by naturally occurring tubular structures, hollow fibers offer unique advantages for a wide range of contemporary applications, such as a high surface-area-to-volume ratio, a low density, and directional mass transport. Although polymeric materials, including conjugated polymer networks, have shown promise for the fabrication of these architectures, their synthesis typically lacks design modularity and often requires sacrificial templates or metal catalysts, limiting their overall sustainability. In this study, we present a new molecular design strategy for metal-free conjugated hollow fibers that can self-assemble into a spongy monolith. Selected monomers undergo rapid Chichibabin-type condensation to form fully conjugated aromatic networks, which simultaneously self-assemble into uniform submicron hollow fibers that, in turn, become entangled to form monoliths. This transformation occurs via single-step, one-pot synthesis without the need for metals, templates, or post-processing. The designed sponge exhibits efficient light absorption, a high surface area, and excellent mass transfer, allowing it to be employed for multiple functions, including oil absorption, the photocatalytic decolorization of dyes, the capture of gas-phase iodine, and thermal insulation. This bottom-up design represents a versatile and sustainable platform for the engineering of hollow-fiber-based materials with broad utility for energy, environmental, and biomedical applications.