Rajasekharan Anand K, Bordes Romain, Sandström Carl, Ekh Magnus, Andersson Martin
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296, Gothenburg, Sweden.
Department of Applied Mechanics, Chalmers University of Technology, SE-41296, Gothenburg, Sweden.
Small. 2017 Jul;13(28). doi: 10.1002/smll.201700550. Epub 2017 Jun 1.
Biological composites display exceptional mechanical properties owing to a highly organized, heterogeneous architecture spanning several length scales. It is challenging to translate this ordered and multiscale structural organization in synthetic, bulk composites. Herein, a combination of top-down and bottom-up approach is demonstrated, to form a polymer-ceramic composite by macroscopically aligning the self-assembled nanostructure of polymerizable lyotropic liquid crystals via 3D printing. The polymer matrix is then uniformly reinforced with bone-like apatite via in situ biomimetic mineralization. The combinatorial method enables the formation of macrosized, heterogeneous composites where the nanostructure and chemical composition is locally tuned over microscopic distances. This enables precise control over the mechanics in specific directions and regions, with a unique intrinsic-extrinsic toughening mechanism. As a proof-of-concept, the method is used to form large-scale composites mimicking the local nanostructure, compositional gradients and directional mechanical properties of heterogeneous tissues like the bone-cartilage interface, for mechanically stable osteochondral plugs. This work demonstrates the possibility to create hierarchical and complex structured composites using weak starting components, thus opening new routes for efficient synthesis of high-performance materials ranging from biomaterials to structural nanocomposites.
生物复合材料由于具有跨越多个长度尺度的高度有序、异质结构，因而展现出卓越的力学性能。在合成的块状复合材料中重现这种有序且多尺度的结构组织具有挑战性。在此，展示了一种自上而下与自下而上相结合的方法，通过3D打印宏观排列可聚合溶致液晶的自组装纳米结构来形成聚合物-陶瓷复合材料。然后通过原位仿生矿化用类骨磷灰石均匀增强聚合物基体。这种组合方法能够形成宏观尺寸的异质复合材料，其中纳米结构和化学成分在微观距离上局部可调。这使得能够通过独特的本征-非本征增韧机制在特定方向和区域精确控制力学性能。作为概念验证，该方法用于形成模仿骨-软骨界面等异质组织的局部纳米结构、成分梯度和定向力学性能的大规模复合材料，以制备力学稳定的骨软骨栓。这项工作证明了使用弱起始组分创建分层且复杂结构复合材料的可能性，从而为从生物材料到结构纳米复合材料等高性能材料的高效合成开辟了新途径。
