Substrate-directed formation of calcium carbonate fibres
Substrate-directed formation of calcium carbonate fibres
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DOI：
10.1039/b813101e
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发表时间：
2009-01-01
影响因子：
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通讯作者：
Meldrum, Fiona C.
中科院分区：
文献类型：
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作者：
Kim, Yi-Yeoun;Kulak, Alex N.;Meldrum, Fiona C.
本文描述了在多元酸二嵌段共聚物存在下在一系列基材上形成碳酸钙纤维，并证明可以通过明智地选择基材和反应条件来控制纤维的形态和结构。虽然方解石和文石单晶上沉淀的纤维被证明是方解石单晶，但玻璃和云母上形成的纤维是无定形的，并且经常表现出显着的螺旋形态。对纤维生长机制的研究表明，所有纤维生长机制都是通过聚合物稳定的前体单元的自组装形成的。形成方解石单晶纤维的颗粒是细长的方解石微晶，纤维的形成可以用定向组装过程来解释，其中前体单元形态和共聚物链表面分布的各向异性促进一维组装。相反，形成无定形纤维的颗粒是球形和无定形的，纤维的形成归因于这些富含共聚物的颗粒的极化。因此，这项工作表明定向聚集过程可以应用于无定形和结晶单元，从而开启了使用嵌段共聚物来控制非常广泛的材料的形态的可能性。
This article describes the formation of fibres of calcium carbonate on a range of substrates in the presence of a polyacid diblock copolymer, and it is demonstrated that the morphologies and structures of the fibres can be controlled by judicious selection of both the substrate and the reaction conditions. While fibres precipitated on single crystals of calcite and aragonite proved to be single crystals of calcite, those formed on glass and mica were amorphous and frequently displayed remarkable helical morphologies. Investigation of the fibre growth mechanism(s) suggests that all formed via the self-assembly of polymer-stabilised precursor units. Particles forming the calcite single-crystal fibres were elongated calcite crystallites, and fibre formation was interpreted in terms of an oriented assembly process, where anisotropy in the precursor unit morphology and surface distribution of copolymer chains promoted one-dimensional assembly. In contrast, the particles that formed amorphous fibres were spherical and amorphous, with fibre formation being attributed to polarisation of these copolymer-rich particles. This work therefore demonstrates that directional aggregation processes can be applied to both amorphous and crystalline units, opening up the possibility of using block copolymers to control the morphologies of a very wide range of materials.