Wang Qihang, Huang Wenyang, Wang Jilin, Long Fei, Fu Zhengyi, Xie Jingjing, Zou Zhaoyong
Hubei Longzhong Laboratory, Wuhan University of Technology, Xiangyang 441000, China; State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
Hubei Longzhong Laboratory, Wuhan University of Technology, Xiangyang 441000, China.
J Colloid Interface Sci. 2025 Feb 15;680(Pt B):24-35. doi: 10.1016/j.jcis.2024.11.076. Epub 2024 Nov 13.
Amorphous phases hold great promise in diverse applications and are widely used by organisms as precursors to produce biominerals with complex morphologies and excellent properties. However, the stabilization and crystallization mechanisms of amorphous phases are not fully understood, especially in the presence of additives. Here, using amorphous calcium carbonate (ACC) as the model system, we systematically investigate the crystallization pathways of amorphous phases in the presence of poly(Aspartic acid) (pAsp) with various chain lengths. Results show that pure ACC transforms into a mixture of calcite and vaterite via the typical dissolution-recrystallization mechanism and 3 % of Asp monomer exhibits negligible effect. However, pAsp with a chain length of only 10 strongly inhibits the aggregation-induced formation of vaterite spheres while slightly delaying the growth of calcite via classical ion-by-ion attachment, thus kinetically favoring the formation of calcite. Moreover, the inhibition effect of calcite growth from solution ions becomes more prominent with the increase of pAsp chain length or concentration, which significantly improves the stability of the amorphous phase and leads to crystallization of spherical or elongated calcite via the nonclassical particle attachment mechanism after pseudomorphic transformation of ACC into vaterite nanoparticles. These results allow us to reach a more comprehensive understanding of the stabilization and crystallization mechanism of ACC in the presence of additives and provide guidelines for controlling the polymorph selection and morphology of crystals during the crystallization of amorphous precursors.
非晶相在各种应用中具有巨大潜力，并且被生物体广泛用作前驱体来生产具有复杂形态和优异性能的生物矿物。然而，非晶相的稳定化和结晶机制尚未完全了解，尤其是在存在添加剂的情况下。在此，我们以非晶碳酸钙（ACC）作为模型体系，系统地研究了在存在不同链长的聚天冬氨酸（pAsp）时非晶相的结晶途径。结果表明，纯ACC通过典型的溶解-再结晶机制转变为方解石和球霰石的混合物，3%的天冬氨酸单体显示出可忽略不计的影响。然而，链长仅为10的pAsp强烈抑制球霰石球的聚集诱导形成，同时通过经典的逐个离子附着略微延迟方解石的生长，从而在动力学上有利于方解石的形成。此外，随着pAsp链长或浓度的增加，从溶液离子中方解石生长的抑制作用变得更加显著，这显著提高了非晶相的稳定性，并导致在ACC伪形转变为球霰石纳米颗粒后通过非经典颗粒附着机制形成球形或拉长的方解石晶体。这些结果使我们能够更全面地了解添加剂存在下ACC的稳定化和结晶机制，并为在非晶前驱体结晶过程中控制晶体的多晶型选择和形态提供指导。
