A nacre-inspired synergistic bridging and film-forming strategy for constructing lightweight, thermally insulating reed scrap/cement composites

Biomass-inorganic composites prepared from agricultural and forestry residues as reinforcing materials are economical, low-carbon, and environmentally friendly. However, their broader application is hindered by poor interfacial compatibility between the organic and inorganic phases, which compromises their overall performance. Inspired by the synergistic enhancements in rigidity and flexibility observed in nacre structures, this study proposes a rapid biomimetic self-assembly strategy to enable synergistic bridging and film formation. In this strategy, chemical anchoring and mechanical interlocking are used to construct a compatible organic-inorganic interface to develop lightweight reed-based composites. Coupling agents collaborated with nano-silica to hydrophobize and graft reed scraps, which formed micro/nanoscale rough interfaces. This promoted the formation of siloxane networks and enhanced mechanical interlocking and chemical bonding with the cement matrix. Concurrently, an emulsion was introduced to establish an interpenetrating network, generate a hydrophobic protective film, and regulate pore structure and interface toughness. Compared to conventional composites, the biomimetic nacre-structured composites exhibited a 104.7% increase in compressive strength, an 82.6% improvement in flexural strength, a 33.9% enhancement in softening coefficient, and also showed good thermal insulation performance. This research proposes a nacre-inspired interface design that expands the utility of reed resources, optimizes the performance of composite materials, and provides a new design idea for the development of thermal insulation green building materials with load-bearing properties.