Toughening of high-strength scalable laminated nanocomposites with discontinuous Bouligand-type architecture through soft flow-shear-induced alignment

Biological materials such as Arapaima gigas scale, pearls, and armadillos, are known for their outstanding strength and toughness due to the fine Bouligand-type configuration. Inspired by Bouligand-type architectures, some design techniques-including self-assembly-have been used to synthesize high-strength biomimetic laminate nanocomposites. Herein, we propose a bottom-up assembly strategy and prepare nanocomposites with Bouligand-type architectures by controlling the soft-flow-shear-induced directional assembly of cellulose-nanofibril building blocks. The resulting biomimetic laminated nanocomposites (BLNC) exhibited high specific flexural strength (FS) of 243. 6 MPa, flexural modulus (FM) of 9715.8 MPa, and specific fracture toughness (FT) of 8.29 MPa m(0.5)/(g/cm(3)), which were 6.06, 4.50, and 1.89 times higher than pure nanolignocellulose bulk (PNLB), respectively. Furthermore, due to the densified twisted Bouligand-type architecture of the micro/nanoscale building blocks, BLNC maintains mechanical liquid resistance stability in several harsh environments, including acid/alkali solutions, boiling water, and liquid nitrogen. It also has excellent dimensional stability and combustion resistance, making it one of the most promising new structural materials in the field of engineering technology.