Widdrat Marc, Schneck Emanuel, Reichel Victoria, Baumgartner Jens, Bertinetti Luca, Habraken Wouter, Bente Klaas, Fratzl Peter, Faivre Damien
Department of Biomaterials, Max Planck Institute of Colloids and Interfaces , Science Park Golm, 14424 Potsdam, Germany.
J Phys Chem Lett. 2017 Mar 16;8(6):1132-1136. doi: 10.1021/acs.jpclett.6b02977. Epub 2017 Feb 23.
It is now recognized that nucleation and growth of crystals can occur not only by the addition of solvated ions but also by accretion of nanoparticles, in a process called nonclassical crystallization. The theoretical framework of such processes has only started to be described, partly due to the lack of kinetic or thermodynamic data. Here, we study the growth of magnetite nanoparticles from primary particles-nanometer-sized amorphous iron-rich precursors-in aqueous solution at different temperatures. We propose a theoretical framework to describe the growth of the nanoparticles and model both a diffusion-limited and a reaction-limited pathway to determine which of these best describes the rate-limiting step of the process. We show that, based on the measured iron concentration and the related calculated concentration of primary particles at the steady state, magnetite growth is likely a reaction-limited process, and within the framework of our model, we propose a phase diagram to summarize the observations.
现在人们认识到，晶体的成核和生长不仅可以通过溶剂化离子的添加发生，还可以通过纳米颗粒的附着发生，这一过程称为非经典结晶。由于缺乏动力学或热力学数据，此类过程的理论框架才刚刚开始被描述。在这里，我们研究了在不同温度下，水溶液中由初级颗粒（纳米级富含铁的无定形前体）生长磁铁矿纳米颗粒的情况。我们提出了一个理论框架来描述纳米颗粒的生长，并对扩散限制和反应限制途径进行建模，以确定哪一个最能描述该过程的限速步骤。我们表明，基于稳态下测得的铁浓度和相关计算得出的初级颗粒浓度，磁铁矿的生长可能是一个反应限制过程，并且在我们的模型框架内，我们提出了一个相图来总结这些观察结果。
