Multifunctional Bionanocomposite Foams with a Chitosan Matrix Reinforced by Nanofibrillated Cellulose

Multifunctional bionanocomposite foams with 3D interconnected networks showing advantageous mechanical properties, thermal insulation, underwater oleophobicity, and biocompatibility, were made from a chitosan matrix reinforced with nanofibrillated cellulose (NFC). The density of the NFC–chitosan nanocomposite foams can be controlled by varying the NFC/chitosan weight ratio and solid content of the suspension in the fabrication process. The mechanical properties and thermal stability of the nanocomposite foams were significantly improved by increasing the ratio of NFC, and effective thermal insulating performance was exhibited for temperature extremes at 0 °C and 70 °C. Moreover, the NFC–chitosan nanocomposite foams showed a highly efficient oil/water separation capacity even at a severe temperature of 90 °C. In addition, the nanocomposite foams possessed good biocompatibility toward L929 mouse fibroblasts. Therefore, the bionanocomposite foams are available for a number of applications, including as disposable and high‐performance filtration media for water purification, packaging, and biological scaffolds. What do you get when you cross a tree with a crab? Bionanocomposite foams that are capable of separating oil/water mixtures. The foams were fabricated by using chitosan (from crabs) as the matrix and nanofibrillated cellulose (from trees) as the filler. These sustainable soft foams display high thermal insulating properties, underwater oleophobicity, and good biocompatibility.