Anisotropic Self-Assembly from Isotropic Colloidal Building Blocks
Anisotropic Self-Assembly from Isotropic Colloidal Building Blocks
复制标题
各向同性胶体砌块的各向异性自组装
DOI：
10.1021/jacs.7b08503
复制
发表时间：
2017
影响因子：
15
通讯作者：
Rey M
中科院分区：
文献类型：
--
作者：
Rey M
球形胶体粒子通常自组装成二维六边形晶格。然而，对于具有软排斥肩的各向同性粒子，理论上已经预测了更复杂的非六方相，但尚未在实验中实现。研究了聚n -异丙基丙烯酰胺（PNiPAm）微凝胶在空气/水界面上的相行为。我们观察到一个复杂的相图，包括具有链状和方形排列的相，它们只在微凝胶存在时形成。我们的实验数据表明，微凝胶在微球周围形成了一个电晕，并诱导了一个软排斥肩，控制了该系统的自组装。通过最小能量计算和有限温度蒙特卡罗模拟，用实验真实的相互作用参数完全再现了所观察到的结构。我们的研究结果表明，通过控制相互作用势，可以从完全各向同性的构建块中实现复杂的各向异性组装模式。
Spherical colloidal particles generally self-assemble into hexagonal lattices in two dimensions. However, more complex, non-hexagonal phases have been predicted theoretically for isotropic particles with a soft repulsive shoulder but have not been experimentally realized. We study the phase behavior of microspheres in the presence of poly(N-isopropylacrylamide) (PNiPAm) microgels at the air/water interface. We observe a complex phase diagram, including phases with chain and square arrangements, which exclusively form in the presence of the microgels. Our experimental data suggests that the microgels form a corona around the microspheres and induce a soft repulsive shoulder that governs the self-assembly in this system. The observed structures are fully reproduced by both minimum energy calculations and finite temperature Monte Carlo simulations of hard core-soft shoulder particles with experimentally realistic interaction parameters. Our results demonstrate how complex, anisotropic assembly patterns can be realized from entirely isotropic building blocks by control of the interaction potential.