image: Schematic illustration of the formation of DCPAs via ambient pressure drying, cross-linking networks, and photographs of the macroscopic performances. view more
Credit: ©Science China Press
They present a straightforward one-pot, mild, and catalyst-free polycondensation strategy via dynamic imine chemistry along with the combination of low-cost and promising ambient pressure drying to construct monolithic dynamic covalent polymer aerogels (DCPAs). The imine bonds derived from the condensation of amino groups and aldehyde groups are capable of empowering the wet gel with strong skeleton. Combining the strong skeleton and high crosslinking density offers an opportunity for transforming the wet gel into aerogels without severe shrinkages via simple ambient pressure drying method.
The lightweight DCPAs possess excellent mechanical properties, such as flexibility, elasticity, processability, etc. Intriguingly, the DCPAs are able to be degraded into soluble monomers and/or dispersible oligomer due to the transimination reactions of imine bonds. Furthermore, the new DCPAs can be generated by adjusting the molar ratio between amino groups and aldehyde groups, thereby realizing the goal of closed-loop recyclability relating to degradation-regeneration-degradation. The DCPAs are also reparable and weldable based on the dynamic properties and ambient pressure drying method, which are fire-new features for aerogels.
This work not only presents a novel class of aerogels and exhibits multifunctionality in various fields including adsorption and thermal insulation, but also provides new research perspective to facilitate the development of both dynamic covalent chemistry and aerogels for applications as smart and environmentally friendly materials.
See the article:
Xinhai Zhang, Jun Zhao, Kai Liu, Guangfeng Li, Dong Zhao, Zhaoming Zhang, Junjun Wan, Xue Yang, Ruixue Bai, Yongming Wang, Wei Zhang*, Xuzhou Yan*
Weldable and closed-loop recyclable monolithic dynamic covalent polymer aerogels
National Science Review, nwac012
https://doi.org/10.1093/nsr/nwac012