Organic–Inorganic Copolymerization Induced Oriented Crystallization for Robust Lightweight Porous Composite

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-11, Vol.20 (48), p.e2403443-n/a
• Main Authors: Yu, Xin, Kong, Kangren, Ma, Xiaoming, Yu, Yadong, Shen, Yinlin, Sang, Yanhua, Wang, Jie, Shen, Sudan, Xu, Xurong, Liu, Zhaoming, Tang, Ruikang
• Format: Article
• Language: English
• Subjects: Acrylamide; Biological effects; Biological materials; bone‐like structure; Calcium phosphates; Copolymerization; Crystallization; Density; Lightweight; mechanical; Mechanical properties; Mechanics; Mechanics (physics); Nanostructure; Oligomers; porous composite; Porous materials; Prepolymers; Robustness; Solid phases; Thermal conductivity; Thermal insulation; Weight reduction
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202403443

Porous composites are important in engineering fields for their lightweight, thermal insulation, and mechanical properties. However, increased porosity commonly decreases the robustness, making a trade‐off between mechanics and weight. Optimizing the strength of solid structure is a promising way to co‐enhance the robustness and lightweight properties. Here, acrylamide and calcium phosphate ionic oligomers are copolymerized, revealing a pre‐interaction of these precursors induced oriented crystallization of inorganic nanostructures during the linear polymerization of acrylamide, leading to the spontaneous formation of a bone‐like nanostructure. The resulting solid phase shows enhanced mechanics, surpassing most biological materials. The bone‐like nanostructure remains intact despite the introduction of porous structures at higher levels, resulting in a porous composite (P‐APC) with high strength (yield strength of 10.5 MPa) and lightweight properties (density below 0.22 g cm−3). Notably, the density‐strength property surpasses most reported porous materials. Additionally, P‐APC shows ultralow thermal conductivity (45 mW m−1 k−1) due to its porous structure, making its strength and thermal insulation superior to many reported materials. This work provides a robust, lightweight, and thermal insulating composite for practical application. It emphasizes the advantage of prefunctionalization of ionic oligomers for organic–inorganic copolymerization in creating oriented nanostructure with toughened mechanics, offering an alternative strategy to produce robust lightweight materials. Porous materials featuring high strength are of great importance. This work introduces a strategy for creating ordered biomimetic nanostructures while simultaneously generating a porous network structure at higher hierarchy levels. It is achieved by prefunctionalization of calcium phosphate oligomers by organic molecules, which builds a relationship between linear organic polymerization and ordered inorganic crystallization during organic–inorganic copolymerization reactions. The ordered structure efficiently enhances the mechanical property of porous composite at low density.