School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
Nat Chem. 2011 Nov 20;4(2):112-7. doi: 10.1038/nchem.1199.
The tiling of surfaces has long attracted the attention of scientists, not only because it is intriguing intrinsically, but also as a way to control the properties of surfaces. However, although random tiling networks are studied increasingly, their degree of randomness (or partial order) has remained notoriously difficult to control, in common with other supramolecular systems. Here we show that the random organization of a two-dimensional supramolecular array of isophthalate tetracarboxylic acids varies with subtle chemical changes in the system. We quantify this variation using an order parameter and reveal a phase behaviour that is consistent with long-standing theoretical studies on random tiling. The balance between order and randomness is driven by small differences in intermolecular interaction energies, which can be related by numerical simulations to the experimentally measured order parameter. Significant variations occur with very small energy differences, which highlights the delicate balance between entropic and energetic effects in complex self-assembly processes.
表面的平铺一直吸引着科学家的注意，不仅因为它本身很有趣，还因为它是控制表面性质的一种方法。然而，尽管随机平铺网络的研究越来越多，但它们的随机性程度（或部分有序性）与其他超分子系统一样，仍然难以控制。在这里，我们表明，间苯二甲酸四羧酸的二维超分子阵列的随机组织随系统中细微的化学变化而变化。我们使用有序参数来量化这种变化，并揭示出与关于随机平铺的长期理论研究一致的相行为。有序性和随机性之间的平衡是由分子间相互作用能的微小差异驱动的，通过数值模拟可以将这些差异与实验测量的有序参数联系起来。随着能量差异的微小变化会发生显著的变化，这突出了在复杂的自组装过程中熵和能量效应之间的微妙平衡。
