“Top-down” fabrication of anisotropic, lightweight, super-amphiphobic, and thermal insulating rattan aerogels

Lightweight and sustainable aerogels have been a growing interest for thermal insulation applications due to current environmental and energy challenges. The design of cellulose-based aerogels with thermal insulation, hydrophobic, and oleophobic performance is the future development direction for building energy-efficient buildings. Herein, an anisotropic, lightweight, super-amphiphobic and thermal insulating rattan aerogel was fabricated by a three-step process of delignification, freeze-drying, and silylation. The prepared rattan aerogel exhibits anisotropic thermal properties with a low thermal conductivity of 0.030 W m–1 K–1 in the radial direction and 0.056 W m–1 K–1 in the axial direction due to the run-through channel skeleton and the structure of the insulating cages. Moreover, the silylated rattan aerogel shows super-amphiphobic performance (water contact angle ∼164° in the cross section and ∼156° in the radial section; oil contact angle ∼158° in the cross section and ∼154° in the radial section). The excellent anisotropic thermal performance, abundance, sustainability, and superb amphiphobicity of the rattan aerogel make it highly promising for green buildings and thermal management applications.