Composition Gradient Cellulose-Aerogel Nanocomposites Regulating Thermal Insulation

Over the last few decades, functional gradient structures have evolved through natural biological systems, while gradient structures lead to tailored mechanical and physical performance due to the gradual structural change. Herein, composition gradient cellulose and aerogel nanocomposites that regulate their thermal insulation and mechanical performance are reported. The as-prepared gradient composite shows a thermal conductivity of 32.2 mW m^-1 K^-1 and flexural modulus of 660 MPa while exhibiting superhydrophobicity and superior reusability. The unique orientation-dependent thermal insulation and mechanical strength arise from the composition gradients formed by the silica aerogel distribution during the cellulose-fiber-percolated network formation, which opens a pathway toward green building thermal insulation materials.