Green and efficient cell wall nano-reconstruction under ambient temperature towards strong cellulosic aerogels

Abstract

Cellulosic aerogels show great promise for diverse applications. However, their widespread adoption is hindered by energy-intensive processing and limited mechanical properties. This work presents a green and efficient approach for strong cellulosic aerogel synthesis through cell wall nano-reconstruction using one-step NaOH (10 wt%) treatment of wood at ambient temperature. The obtained cellulosic aerogel (wood aerogel) showed partially preserved hierarchical structure and nanofibril networks filled lumen, leading to a combination of high specific surface area (202 m² g⁻¹) and a high yield strength (4.3 MPa). The generation of mesoporosity and the building of nanofibril networks were studied in detail. NaOH provided cell wall swelling and partial extraction of deacetylated xylan, generating nanoporosity in the cell wall. The extracted xylan then aggregated and rearranged into nanofibril networks occupying the lumen. The technology developed for wood aerogel synthesis and the understanding of wood aerogel formation pave the way for green cell wall nanoengineering towards advanced materials design.