Ice-template supramolecular assembly for constructing degradable hyperbranched polyamide/cellulose aerogels for formaldehyde capture

To address the issues of low formaldehyde adsorption capacity in bio-based aerogels and the non-degradability of traditional adsorbents, this study proposes a “directed cryo-assisted in-situ supramolecular composite” strategy to prepare a composite aerogel that combines ultra-high formaldehyde adsorption capacity with rapid biodegradability. Through in-situ self-assembly of a hydrogen-bonded network of water-soluble hyperbranched polyamide (HBPA) and cellulose nanofibers (CNF), combined with directed cryo-ice template technology, vertically oriented multi-level layered channels were constructed, effectively solving the problems of functional molecule aggregation and low mass transfer efficiency. The composite aerogel exhibited an excellent honeycomb network structure, with a yield strength of 14.46 kPa and a specific surface area of 12.76 m 2 /g. Owing to the synergistic effect of a high density of chemical adsorption sites and efficient mass transfer channels, the material achieves a formaldehyde removal efficiency of 99.03 %, with an adsorption capacity of 698.77 mg/g—far surpassing that of commercial activated carbon. Moreover, it rapidly disintegrated into moist soil within 20 days, thereby eliminating the secondary pollution issues associated with traditional adsorbents. This work offers new insights into the development of high-performance, environmentally friendly materials for indoor formaldehyde pollution control. • Directional freezing-assisted in situ supramolecular composite. • Ultra-high HCHO adsorption capacity of 698.77 mg/g. • Vertically aligned honeycomb pore structure. • Rapid biodegradability within 20 days in moist soil.