Dramatic Enhancement and Integration of Properties in Pork Belly‐Inspired All‐Biomass Composite Films via Facile, Sustainable, and Controllable Design

Although all‐biomass composite films that integrate electromagnetic interference (EMI) shielding, thermal management, and mechanical properties are promising alternatives to conventional flexible electronic materials owing to the renewability, degradability, and sustainability, the substantial performance shortcomings severely limit the practical availability of these materials. In this study, an effective layer‐by‐layer assembly strategy inspired by the hierarchical structure of pork belly was proposed to fabricate alternating multilayer (AM) biomimetic composite films composed of cellulose nanofibers (CNFs), graphitized carbon nanosheets (GCNs), and gelatin. Efficient stress transfer, phonon transport, and electromagnetic attenuation were achieved through the construction of a robust hierarchical multilayer architecture enabled by the synergistic interactions among GCNs, CNFs, and gelatin. The results showed that the AM‐7 composite film exhibited a tensile strength of 121.20 MPa, which was increased by 266% and 199% compared with CF and CG composite films, respectively. An enhanced in‐plane thermal conductivity of 6.34 W·m − 1 ·K − 1 was achieved, and the EMI shielding effectiveness attained 56.35 dB. This work provides a sustainable strategy for the high‐value utilization of agricultural waste while offering new insights into the rational design of high‐performance multifunctional biomass‐based composites.