Behrens Manja Annette, Franzén Alexandra, Carlert Sara, Skantze Urban, Lindfors Lennart, Olsson Ulf
Division of Physical Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
AstraZeneca R&D Mölndal, Pharmaceutical Development, Pepperedsleden 1, SE-431 83 Mölndal, Sweden.
Soft Matter. 2025 Mar 19;21(12):2349-2354. doi: 10.1039/d4sm01544d.
Ostwald ripening of crystalline and amorphous nanoparticle dispersions of a model organic compound are compared. While amorphous nanoparticles show a rapid ripening on the timescale of minutes, the crystalline nanoparticles do not ripen within the timescale of weeks. A metastable zone for crystal growth, presumably involving a free energy barrier, is identified, and we propose that this explains the absence of Ostwald ripening in the nanocrystal dispersion. As Ostwald ripening is a process typically occurring near equilibrium, even a small barrier may prevent ripening.
比较了一种模型有机化合物的结晶和非晶态纳米颗粒分散体的奥斯特瓦尔德熟化过程。非晶态纳米颗粒在几分钟的时间尺度上显示出快速熟化，而结晶纳米颗粒在数周的时间尺度内不会熟化。确定了晶体生长的亚稳区，推测这涉及一个自由能垒，并且我们认为这解释了纳米晶体分散体中奥斯特瓦尔德熟化的缺失。由于奥斯特瓦尔德熟化是一个通常在接近平衡时发生的过程，即使是一个小的势垒也可能阻止熟化。
