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Natural polymer substrates are gaining attention as substitutes for plastic substrates in electronics, aiming to combine high performance, intricate shape deformation, and environmental sustainability. Herein, natural wood veneer is converted into a transparent wood film (TWF) substrate. The combination of 3D printing and origami technique is established to create programmable wood-based origami electronics, which exhibit superior flexibility with high tensile strength (393 MPa) due to the highly aligned cellulose fibers and the formation of numerous intermolecular hydrogen bonds between them. Moreover, the flexible TWF electronics exhibit editable multiplexed configurations and maintain stable conductivity. This is attributed to the strong adhesion between the cellulose-based ink and TWF substrate by non-covalent bonds. Benefiting from its anisotropic structure, the programmability of TWF electronics is achieved through sequentially folding into predesigned shapes. This design not only promotes environmental sustainability but also introduces its customizable shapes with potential applications in sensors, microfluidics, and wearable electronics. Wood-based electronics are typically constrained in their ability to undergo complex shape deformation. Here, authors integrate transparent wood film and cellulose-based conductive ink for flexible electronic origami devices that have been demonstrated as a proof-of-concept for human motion sensors. [ABSTRACT FROM AUTHOR]

Foam thermal insulators are indispensable for prevailing energy‐saving engineering, however their widespread use brings intractability such as unsustainability, "white pollution", and fire hazards. The emergence of bio‐based foams is highly appreciated, but the fabrication approaches are economically unattractive and/or the product properties are inferior, making their large‐scale implementation unviable. Herein, a versatile, thermally remoldable phosphate‐containing polyurethane composite foam (LPU‐G) is constructed from natural lignin and expanded graphite flakes via an atmospheric pressure and scalable one‐pot strategy. The optimal LPU‐G exhibits exceptional mechanical strength, capable of supporting over 6000 times its weight without significant deformation. Moreover, the LPU‐G demonstrates the desired multifunctionality in handling extreme circumstances, including humidity‐tolerant thermal insulation, superb water vapor barrier, and withstanding ≈1200 °C flame without ignition. Based on the "expansion‐conductivity" micro‐mechanism, LPU‐G is the first foam material to be constructed as a sensitive fire alarm system with an ultra‐long alarm time (>1800 s). Surprisingly, LPU‐G can be rapidly upcycled into recyclable bulk composites for a second life through simple thermo‐molding processes rooted in the multi‐dynamic behavior of the phosphate, carbamate, and hydrogen bonds. The easy‐to‐scale LPU‐G represents a new generation of thermal insulators that address concerns regarding unsustainability, high cost, fire risk, and inferior mechanical properties. [ABSTRACT FROM AUTHOR]