Plasma-textured bamboo metamaterials with tree frog-inspired hierarchical topography and self-healing interface for synergistic acoustics

Abstract

Natural bamboo fiber (BF) composites offer a sustainable alternative to non-biodegradable synthetic polymers (e.g., polypropylene, PP) in noise control, yet face dual challenges: disordered surface morphology limits acoustic energy conversion, and weak fiber-matrix interfacial bonding induces performance degradation. Inspired by the multi-scale sound-dissipation architecture of tree frog skin (micro-papillae attenuating 3000–5000 Hz noise and nanofolds reducing reflectivity by 62 %), we propose a cross-scale synergistic strategy integrating plasma-induced surface reconstruction (300W/180s/O₂) and covalent-supramolecular dual-network (DCN-PEI) interfacial engineering. Plasma treatment constructs “groove-particle” hierarchical structures (groove depth: 1.2 ± 0.3 μm, particle diameter: 80 ± 20 nm), while KH550 silanization forms Si–O–C bonds increasing the contact angle to 111.1° ± 2.3°, mimicking the hydrophobic barrier function of glycoprotein mucus. The biomimetic composite achieves: 1) Record-high sound absorption coefficient (SAC) (α = 0.82 ± 0.03 at 2000–4000 Hz, 35 % enhancement vs. untreated BF); 2) Ultrahigh transmission loss (>55 dB at 1000–6300 Hz, thickness: 6 mm, density: 0.5 g/cm³), outperforming palm fiber by 42 % in SAC and commercial PP board by 2.6-fold in noise reduction (29.6 dB vs. 11.6 dB); 3) Self-healing functionality with 34 % ± 3 % scratch depth recovery via dynamic H-bonds and transesterification. This work pioneers cross-scale integration of biological acoustic mechanisms and self-repair, establishing a “morphology-interface-function” trilevel design paradigm for sustainable acoustics.