Molecularly Woven Polymer Aerogels.

Aerogels with abundant nanopores and large specific surface areas have extensive potential in various applications but are constrained by fragility and difficulty in degradation. Currently, the exploration of adaptive and reprocessing aerogels has become increasingly urgent, as the demand for intelligent and sustainable materials intensifies. Here, we present a molecular weaving strategy to construct molecularly woven polymer aerogels (WPAs) via catalyst-free aldimine condensation between prewoven aldehyde-functionalized Cu(I) bisphenanthroline (Cu(PBD)) and flexible 4,4'-diaminodibenzyl (DB). The key feature of this system consists entirely of dense woven nodes that can be readily activated by external stimuli, where Cu(I) ions can also be reversibly removed as needed, while preserving porous structures. Consequently, we achieve adjustable mechanical properties of WPAs, with a 10-fold enhancement in elasticity after removing Cu(I) ions. Moreover, the destroyed WPAs demonstrate a straightforward reprocessing capacity rather than tedious monomer recovery due to the dissociation of Cu(I)-coordination bonds, the activation of sequential polymer thread motions, and the accelerated imine bond exchange enabled by adjacent Cu(I) ions. This work offers a new perspective on designing customizable and sustainable aerogels and verifies the feasibility of the emergent molecularly woven technique in a more complex functional material system.