Cacciuto A, Auer S, Frenkel D
FOM Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands.
Phys Rev Lett. 2004 Oct 15;93(16):166105. doi: 10.1103/PhysRevLett.93.166105.
We report simulations of crystal nucleation in binary mixtures of hard spherical colloids with a size ratio of 1:10. The stable crystal phase of this system can be either dense or expanded. We find that, in the vicinity of the solid-solid critical point where the crystallites are highly compressible, small crystal nuclei are less dense than large nuclei. This phenomenon cannot be accounted for by either classical nucleation theory or by the Gibbsian droplet model. We argue that the observed behavior is due to the surface stress of the crystal nuclei. The observed effect highlights a general deficiency of the most frequently used thermodynamic theories for crystal nucleation. Surface stress should lead to an experimentally observable expansion of crystal nuclei of colloids with short-ranged attraction and of globular proteins.
我们报告了尺寸比为1:10的硬球形胶体二元混合物中晶体成核的模拟情况。该系统的稳定晶相可以是致密的或膨胀的。我们发现，在微晶高度可压缩的固 - 固临界点附近，小晶核比大晶核密度小。这种现象既不能用经典成核理论也不能用吉布斯液滴模型来解释。我们认为观察到的行为是由于晶核的表面应力。观察到的效应突出了晶体成核最常用热力学理论的一个普遍缺陷。表面应力应该会导致具有短程吸引力的胶体和球状蛋白质的晶核在实验中可观察到的膨胀。
