Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus C, Denmark.
Nanotechnology. 2011 Jun 3;22(22):225601. doi: 10.1088/0957-4484/22/22/225601. Epub 2011 Apr 1.
We report a simple, rapid and cost-effective method based on evaporation induced assembly to grow 3D binary colloidal assemblies on a hydrophobic/hydrophilic substrate by simple drop casting. The evaporation of a mixed colloidal drop results in ring-like or uniform area deposition depending on the concentration of particles, and thus assembly occurs at the periphery of a ring or uniformly all over the drop area. Binary colloidal assemblies of different crystal structure are successfully prepared over a wide range of size ratios (γ = small/large) from 0.06 to 0.30 by tuning the γ of the micro- and nanoparticles used during assembly. The growth mechanism of 3D binary colloidal assemblies is investigated and it is found that electrostatic forces facilitate assembly formation until the end of the evaporation process, with capillary forces also playing a role. In addition, the effects of solvent type, humidity, and salt concentration on crystal formation and ordering behaviour are also examined. Furthermore, long range, highly ordered binary colloidal assemblies can be fabricated by the choice of a low conducting solvent combined with evaporation induced assembly.
我们报告了一种简单、快速且经济高效的基于蒸发诱导组装的方法，可通过简单的滴铸在疏水/亲水基底上生长 3D 二元胶体组装体。混合胶体滴的蒸发会导致环状或均匀区域沉积，具体取决于颗粒浓度，因此组装会发生在环的外围或滴区域的整个表面上。通过调节组装过程中使用的微纳米粒子的γ值，可以成功制备出不同晶体结构的二元胶体组装体，γ值范围很广，从 0.06 到 0.30。研究了 3D 二元胶体组装体的生长机制，发现静电相互作用有助于组装体的形成，直到蒸发过程结束，毛细作用力也起到了一定的作用。此外，还研究了溶剂类型、湿度和盐浓度对晶体形成和有序行为的影响。此外，通过选择低电导率溶剂并结合蒸发诱导组装，可以制备具有长程、高度有序的二元胶体组装体。
