The demand for both strength and toughness is perpetual in fiber-reinforced composites. Unfortunately, both properties are often mutually exclusive. As the mechanical properties of the composites are highly dependent on their interfacial properties, engineering interfaces between the fiber and matrix would be vital to overcome the conflict between strength and toughness. Herein, inspired by the physical interfacial architecture of grassroots-reinforced soil composites, a porous carbon nanotube−Mg(OH) 2 /MgO hybrid structure was constructed on the fiber surface via water electrolysis reaction and electrophoretic deposition process. The effects of the porous structure on the fiber filaments' mechanical properties, as well as the thickness on the interfacial properties, were all investigated. The results showed that fully covered porous structures on the fiber surface slightly enhanced the reliability of a single fiber in terms of mechanical properties by bridging the surface defects on the fiber. The interfacial shear strength and toughness of the porous structure-coated fiber/resin composite reached up to 92.3 MPa and 121.2 J/m 2 , respectively. These values were 61.30 and 121.98% higher than those of pristine fiber/resin composites, respectively. The strengthening effect was ascribed to the synergistic effects that improved numerous interfacial bonding areas and mechanical interlocking morphologies. The toughening mechanism was related to crack deflection, microcrack generation, and fracture of the porous structure during interfacial failure. Additional numerical studies by finite element analysis further proved the enhancement mechanism. Overall, the proposed method looks promising for producing advanced carbon fiber-reinforced polymer composites with excellent strength and toughness.

Thin films are ideal building blocks for hyperacute sensors and flexible electronic devices. However, most thin films either lack strength for practical applications or are not compatible with mass-production processes. Here, we reported an orb-webinspired polymer-carbon nanocomposite-based, strong, lightweight, flexible mesh-type film that was compatible with standard microfabrication and suitable for high-performance acoustic sensing. Taking advantage of the superior mechanical strength of the three-dimensional (3D) heterogeneous nanocomposites constructed by one-dimensional (1D), two-dimensional (2D) carbon-based nanoparticles and polymer matrixes, we fabricated a 564-nm-thick mesh-type film that could be suspended freely both in liquid and air, and folded and stretched repeatedly over a macroscale opening. The sensing application of the mesh-type nanocomposite film was further demonstrated, which could even detect weak airborne sound waves with high fidelity, large dynamic range (>115 dB), and fine frequency resolution (<0.05 Hz) over the audible range. This work provides an approach to manufacturing designable, thin film-based flexible devices across scales with superior performance.