State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.
Langmuir. 2010 Dec 7;26(23):17936-42. doi: 10.1021/la103778m. Epub 2010 Oct 25.
We present a novel and simple method to fabricate two-dimensional (2D) poly(styrene sulfate) (PSS, negatively charged) colloidal crystals on a positively charged substrate. Our strategy contains two separate steps: one is the three-dimensional (3D) assembly of PSS particles in ethanol, and the other is electrostatic adsorption in water. First, 3D assembly in ethanol phase eliminates electrostatic attractions between colloids and the substrate. As a result, high-quality colloidal crystals are easily generated, for electrostatic attractions are unfavorable for the movement of colloidal particles during convective self-assembly. Subsequently, top layers of colloidal spheres are washed away in the water phase, whereas well-packed PSS colloids that are in contact with the substrate are tightly linked due to electrostatic interactions, resulting in the formation of ordered arrays of 2D colloidal spheres. Cycling these processes leads to the layer-by-layer assembly of 3D colloidal crystals with controllable layers. In addition, this strategy can be extended to the fabrication of patterned 2D colloidal crystals on patterned polyelectrolyte surfaces, not only on planar substrates but also on nonplanar substrates. This straightforward method may open up new possibilities for practical use of colloidal crystals of excellent quality, various patterns, and controllable fashions.
我们提出了一种新颖而简单的方法，可在带正电荷的基底上制造二维（2D）聚（苯乙烯磺酸盐）（PSS，带负电荷）胶体晶体。我们的策略包含两个独立的步骤：一是在乙醇中进行 PSS 颗粒的三维（3D）组装，二是在水中进行静电吸附。首先，在乙醇相中进行 3D 组装可以消除胶体与基底之间的静电吸引力。因此，很容易产生高质量的胶体晶体，因为静电吸引力不利于胶体颗粒在对流自组装过程中的运动。随后，胶体球的顶层在水相中被洗掉，而与基底接触的紧密堆积的 PSS 胶体由于静电相互作用而紧密相连，从而形成有序的二维胶体球阵列。循环这些过程会导致具有可控层的 3D 胶体晶体的逐层组装。此外，该策略可扩展到在图案化聚电解质表面上制造图案化的 2D 胶体晶体，不仅在平面基底上，而且在非平面基底上。这种简单的方法可能为高质量、各种图案和可控样式的胶体晶体的实际应用开辟新的可能性。
