Transparent Nacre‐like Composites Toughened through Mineral Bridges

Abstract

Bulk materials with remarkable mechanical properties have been developed by incorporating design principles of biological nacre into synthetic composites. However, this potential has not yet been fully leveraged for the fabrication of tough and strong materials that are also optically transparent. In this work, a manufacturing route that enables the formation of nacre‐like mineral bridges in a bioinspired composite consisting of glass platelets infiltrated with an index‐matching polymer matrix is developed. By varying the pressure applied during compaction of the glass platelets, composites with tunable levels of mineral bridges and platelet interconnectivity can be easily fabricated. The effect of platelet interconnectivity on the mechanical strength and fracture behavior of the bioinspired composites is investigated by performing state‐of‐the‐art fracture experiments combined with in situ electron microscopy. The results show that the formation of interconnections between platelets leads to bulk transparent materials with an unprecedented combination of strength and fracture toughness. This unusual set of properties can potentially fulfill currently unmet demands in electronic displays and related technologies.

Glass Transition Temperature Regulates Mechanical Performance in Nacre‐Mimetic Nanocomposites

“…Nature's lightweight, load‐bearing, and sustainable materials with hierarchical architecture and synergetic mechanical performance inspire the design of bioinspired nanocomposite with strong, stiff, and tough behavior. [ 1–5 ] Nacre with its brick and mortar architecture continues to be one role model for such composites, which are tackled by several preparation routes to realize highly reinforced nanocomposites (>50 wt% of platelets), including layer‐by‐layer (LbL), [ 6 ] multi‐layer deposition, [ 7 ] filtration, [ 8–11 ] directional freezing, [ 12–14 ] 3D printing, [ 15 ] and evaporative self‐assembly. [ 16,17 ] Such methods vary in terms of time‐consumption, scalability, and total amount of steps, yet still provide an efficient and controllable structure.…”

“…[ 16,17 ] Such methods vary in terms of time‐consumption, scalability, and total amount of steps, yet still provide an efficient and controllable structure. Additionally, different reinforcements have been useful to provide a nacre‐like structure, among them, clays, [ 11,16,18,19 ] graphene, [ 20–22 ] mxene, [ 10,23 ] glass, [ 8,9 ] lignocellulose, [ 14 ] and even polymer‐based systems. [ 24,25 ] Furthermore, the variation of the size and aspect ratio ( d / t ) of the reinforcement has allowed to obtain control over the structure formation, deformation mechanisms, and mechanical properties, demonstrating the importance of a precise architecture.…”

Advancing the Mechanical Performance of Glasses: Perspectives and Challenges

“…Progress has continued with improved transparency in strong nacreous glasses, yet modest toughness. [ 281 ] It was recently shown that closely index matching the PMMA with the glass can markedly improve transparency (Figure 12a). Centrifuging the glass–PMMA mixture before the PMMA has been cured increases the glass volume fraction and induces a layered, ordered structure (Figure 12b).…”

Heat-Induced Transformation of Luminescent, Size Tuneable, Anisotropic Eu:Lu(OH)2Cl Microparticles to Micro-Structurally Controlled Eu:Lu2O3 Microplatelets

“…Indeed, polymer composites containing aligned alumina platelets, where the microstructure of the composite led to improved mechanical properties of the macroscopic sample were recently reported [7]. Moreover, by matching the refractive index of glass microplatelets and polymethyl methacrylate host, structurally similar materials proved to additionally gain optical transparency in the obtained composites [8,9]. A similar bottom-up approach can also be applied to other particle geometries.…”

“…This strategy may represent a valuable and costeffective alternative to the growth of single crystals of the same material, especially when the growth of single crystals is limited with respect to accessible geometries, doping homogeneity or high temperatures [5,6]. Moreover, the intentional assembly of microor nanoparticles holds promises for generating particle-based macroscopic ceramics and composites, in which the particle structure and morphology can impart functionality to the assembly [7][8][9][10]. Indeed, polymer composites containing aligned alumina platelets, where the microstructure of the composite led to improved mechanical properties of the macroscopic sample were recently reported [7].…”