Self-templating assembly of soft microparticles into complex tessellations
Self-templating assembly of soft microparticles into complex tessellations
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DOI：
10.1038/s41586-020-2341-6
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发表时间：
2020-06-01
期刊：
影响因子：
64.8
通讯作者：
Isa, Lucio
中科院分区：
文献类型：
--
作者：
Grillo, Fabio;Fernandez-Rodriguez, Miguel Angel;Isa, Lucio
软微粒的六边形自组装单层充当第二层相同颗粒的模板，迫使形成具有意想不到的结构对称性和复杂性的图案。在自组装胶体晶体中编码阿基米德和不规则镶嵌，为从低摩擦涂层到光电超材料等应用提供了前所未有的结构依赖特性(1-7)。然而，尽管大量计算研究甚至通过简单的粒子间相互作用预测了奇异结构 (8-12)，但复杂的非六方晶体的实现在实验上仍然具有挑战性 (13-18)。在这里，我们表明，吸附在液-液界面上的两个六边形堆积的相同球形软微粒单层可以组装成大量二维微图案，只要它们一个接一个地固定在固体基质上。第一个单层保留其最低能量的六边形结构，并充当模板，第二个单层的粒子被迫在其上重新排列。两个晶格之间的挫败感引发了对称性，如果所有粒子都在一步中组装起来，这种对称性就不会出现。只需改变两个单层的堆积分数，我们不仅可以获得矩形和蜂窝晶格等低配位结构，而且还可以获得编码非规则镶嵌的菱形、六边形和人字形超晶格。这是在没有定向键合的情况下实现的，并且形成的结构是平衡结构：分子动力学模拟表明，这些结构是热力学稳定的，并且由短程排斥相互作用发展而来，使它们易于预测，从而为复杂微图案的合理设计提供了途径。
A hexagonal self-assembled monolayer of soft microparticles acts as the template for a second layer of the same particles, forcing the formation of patterns with unexpected structural symmetries and complexities.Encoding Archimedean and non-regular tessellations in self-assembled colloidal crystals promises unprecedented structure-dependent properties for applications ranging from low-friction coatings to optoelectronic metamaterials(1-7). Yet, despite numerous computational studies predicting exotic structures even from simple interparticle interactions(8-12), the realization of complex non-hexagonal crystals remains experimentally challenging(13-18). Here we show that two hexagonally packed monolayers of identical spherical soft microparticles adsorbed at a liquid-liquid interface can assemble into a vast array of two-dimensional micropatterns, provided that they are immobilized onto a solid substrate one after the other. The first monolayer retains its lowest-energy hexagonal structure and acts as a template onto which the particles of the second monolayer are forced to rearrange. The frustration between the two lattices elicits symmetries that would not otherwise emerge if all the particles were assembled in a single step. Simply by varying the packing fraction of the two monolayers, we obtain not only low-coordinated structures such as rectangular and honeycomb lattices, but also rhomboidal, hexagonal and herringbone superlattices encoding non-regular tessellations. This is achieved without directional bonding, and the structures formed are equilibrium structures: molecular dynamics simulations show that these structures are thermodynamically stable and develop from short-range repulsive interactions, making them easy to predict, and thus suggesting avenues towards the rational design of complex micropatterns.