Bioinspired Nacre-like Ceramic-polymer Composites with Multiscale Layered and Gradient Structures

doi:10.15541/jim20250341

Abstract

Abstract:

Due to their intrinsic brittleness and high sensitivity to structural flaws, ceramics face a fundamental limitation in applications that require mechanical load-bearing capacity, impact resistance, and reliable performance under complex service conditions. Natural ceramic-based materials, such as nacre, have evolved intricate multiscale structures through long-term evolutionary processes, effectively integrating high strength and fracture toughness, offering valuable inspiration for the design of synthetic ceramics. This study utilized an accumulative rolling technique combined with a layer-by-layer assembly process to fabricate bioinspired ceramic-polymer composites featuring nacre-like layered and gradient structures at the multiscale. The composites exhibit a characteristic nacre-like “brick-and-mortar” architecture at the microscale, as well as periodic or gradient variations in ceramic content at the mesoscale, collectively forming bioinspired multiscale layered and gradient structures. The mechanical properties of the bioinspired composites were systematically investigated and compared with uniform composites with equivalent ceramic content. The relationships between the bioinspired structures, mechanical properties, and damage characteristics were elucidated. The results demonstrate that the bioinspired composites exhibit variations of up to several times in local hardness and elastic modulus along the thickness direction. In particular, the gradient composite with a “soft-hard-soft” configuration achieves superior strength-toughness synergy, demonstrating significantly higher strength, work of fracture, and fracture and impact toughness compared to the uniform materials with the same ceramic content. This enhancement is primarily attributed to the ability of this architecture to broaden stress distribution, reduce local stress concentrations, and facilitate extensive dissipation of mechanical energy. This study provides a useful reference and guidance for the structural design of strong and tough bioinspired ceramic-polymer composites.

Key words: ceramic-polymer composite, bioinspired design, multiscale structure, gradient, mechanical property

CLC Number:

TB332

GAO Kefeng, HE Xinxin, LIU Zengqian, ZHANG Zhefeng. Bioinspired Nacre-like Ceramic-polymer Composites with Multiscale Layered and Gradient Structures[J]. Journal of Inorganic Materials, 2026, 41(5): 573-582.

Figures/Tables 6

Fig. 1 Schematic illustration of the fabrication procedure of the bioinspired nacre-like ceramic-polymer composites and the formation mechanism of the brick-and-mortar structure (a) Schematic of the accumulative rolling process; (b) Thin sheets with varying graphite flake contents produced via rolling; (c) Stacking configurations of thin sheets for the fabrication of bioinspired multiscale layered and gradient composites; (d) Microstructure of the porous ceramic scaffold; (e) Infiltration of the scaffold with liquid monomers; (f) Nanoscale structure of the resulting bioinspired composites

Fig. 2 Microstructures on the through-thickness cross section of bioinspired nacre-like ceramic-polymer composites (a) Through-thickness 3D XRT images (L1, G2) and SEM images (L2, G1) of bioinspired composites; (b) Representative SEM images of mesoscale layers with varying ceramic contents; (c) SEM image of the interface between layers with different ceramic contents; (d, e) Magnified SEM images of mineral bridges (d) and nanoasperities (e) on the ceramic platelets

Fig. 3 Variations in local mechanical properties of nanoindentation hardness H and modulus E across the thickness direction of bioinspired nacre-like ceramic-polymer composites (a, b) Local variations in nanoindentation hardness (a) and modulus (b) in the L1 and L2 composites; (c, d) Local variations of nanoindentation hardness (c) and modulus (d) in the G1 and G2 composites. Colorful figures are available on website

Fig. 4 Mechanical properties of bioinspired ceramic-polymer composites compared with uniform composite (a) Representative load-displacement curves of composites in three-point bending tests; (b, c) Corresponding nominal flexural strength (b) and work of fracture (c) of composites; (d, e) Representative fracture morphologies of uniform (d) and G2 (e) composites after flexural testing; (f) Representative load-displacement curves of composites in SENB tests; (g, h) Plain-strain fracture toughness for crack initiation KIC (g) and impact toughness αk (h) of composites

Fig. 5 Finite element modelling simulation results of the von Mises stress and strain distributions in bioinspired G2 composite compared with uniform composite (a, b) Distributions of von Mises stress (a) and strain (b) in the bioinspired G2 and uniform composites under three-point bending; (c, d) Distributions of von Mises stress (c) and strain (d) in the bioinspired G2 and uniform composites under single-edge notched bending

Fig. 6 Comparison of mechanical properties between bioinspired composites and other ceramic-polymer composites (a) Variation of flexural strength as a function of the content of inorganic phase in PMMA-based ceramic-polymer composites; (b) Comparison of flexural strength and fracture toughness KIC between current bioinspired composites and other ceramic-polymer composites for dental restoration

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