Converting wheat straw waste into a high-performance material is necessary and challenging from the perspective of “waste to wealth” and green development. This study successfully fabricated an anisotropic ultrastrong, light-transmitting, and biodegradable film from wheat straw using the top-down strategy. The resulting wheat straw film (WSF) exhibited superb tensile strength (up to 754.34 MPa), specific strength (up to 580.26 MPa cm3 g−1), and toughness (up to 18.72 MJ m−3) due to the well-aligned cellulose nanofibers after the chemical treatment and densification. Moreover, the WSF exhibited remarkable transmittance (≈74%), haze (≈79%), and anisotropic optical properties. Considering its degradability and excellent performance, the full wheat straw-based film could be applied to sustainable biomass-based products (such as optoelectronic devices and flexible electronics).
