Structure and Properties of Nanocomposites Formed by the Occlusion of Block Copolymer Worms and Vesicles Within Calcite Crystals
Structure and Properties of Nanocomposites Formed by the Occlusion of Block Copolymer Worms and Vesicles Within Calcite Crystals
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DOI：
10.1002/adfm.201504292
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发表时间：
2016-03-02
影响因子：
19
通讯作者：
Meldrum, Fiona C.
中科院分区：
文献类型：
--
作者：
Kim, Yi-Yeoun;Semsarilar, Mona;Meldrum, Fiona C.
本文介绍了一种实验通用的策略，用于生产无机/有机纳米复合材料，在纳米和介观尺度的微观结构的控制。从生物矿物中获得灵感，CaCO 3与阴离子二嵌段共聚物蠕虫或囊泡共沉淀，以产生方解石单晶，其包藏高密度的有机组分。这种方法也可以扩展到生成复杂的结构，其中晶体内部图案化有不同形态的纳米物体。使用高分辨率同步辐射粉末X射线衍射和振动光谱的纳米复合晶体的广泛表征演示了闭塞如何影响晶格的短程和长程有序。通过与含有胶乳颗粒和共聚物胶束的纳米复合晶体的比较，结果表明，这些闭塞对晶格的影响主要是由无机晶体和有机纳米物体之间的界面，而不是闭塞的大小。这是支持蠕虫闭塞在方解石，这揭示了平坦的共聚物蠕虫晶体表面上，随后由埋葬和空隙形成的原位原子力显微镜研究。最后，使用纳米压痕技术，这表明它们具有接近生物方解石的硬度的纳米复合晶体的机械性能。
This article describes an experimentally versatile strategy for producing inorganic/organic nanocomposites, with control over the microstructure at the nano-and mesoscales. Taking inspiration from biominerals, CaCO3 is coprecipitated with anionic diblock copolymer worms or vesicles to produce single crystals of calcite occluding a high density of the organic component. This approach can also be extended to generate complex structures in which the crystals are internally patterned with nano-objects of differing morphologies. Extensive characterization of the nanocomposite crystals using high resolution synchrotron powder X-ray diffraction and vibrational spectroscopy demonstrates how the occlusions affect the short and long-range order of the crystal lattice. By comparison with nanocomposite crystals containing latex particles and copolymer micelles, it is shown that the effect of these occlusions on the crystal lattice is dominated by the interface between the inorganic crystal and the organic nano-objects, rather than the occlusion size. This is supported by in situ atomic force microscopy studies of worm occlusion in calcite, which reveal flattening of the copolymer worms on the crystal surface, followed by burial and void formation. Finally, the mechanical properties of the nanocomposite crystals are determined using nanoindentation techniques, which reveal that they have hardnesses approaching those of biogenic calcites.