Lee Don Keun, Kim Young Hwan, Kim Chang Woo, Cha Hyun Gil, Kang Young Soo
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
J Phys Chem B. 2007 Aug 9;111(31):9288-93. doi: 10.1021/jp072612c. Epub 2007 Jul 17.
Although several methods (e.g., self-assembly, spin coating, etc.) have been explored for making a monolayer film of nanoparticles, the monolayer on a substrate is typically smaller than 1 micromx1 microm in certain regions. The approach is not ideally suitable for generating a highly ordered and close-packed homogeneous vast monolayer of nanoparticles, which is potentially important for applications. In this report, the preparation of the vast monolayer films of Fe3O4 nanoparticles with a wide range such as that over 3.25 micromx3.95 microm is reported. Their TEM images showed a two-dimensional assembly of Fe3O4 nanoparticles, demonstrating the uniformity of these nanoparticles. The formation of a Langmuir monolayer of the oleic acid-coated Fe3O4 nanoparticles mixed with stearic acid molecules at the air/water interface and its stability were studied with a pressure-area isotherm curve. TEM and BAM studies demonstrated that increasing surface pressure resulted in a transition from well-separated domains of nanoparticles complex to well-compressed, monoparticulate layers.
尽管已经探索了几种制备纳米颗粒单层膜的方法（例如，自组装、旋涂等），但在某些区域，基底上的单层通常小于1微米×1微米。该方法并不理想地适用于生成高度有序且紧密堆积的均匀大面积纳米颗粒单层，而这对于应用可能很重要。在本报告中，报道了制备范围广泛（例如超过3.25微米×3.95微米）的Fe3O4纳米颗粒大面积单层膜。它们的透射电子显微镜（TEM）图像显示了Fe3O4纳米颗粒的二维组装，证明了这些纳米颗粒的均匀性。利用压力-面积等温线曲线研究了油酸包覆的Fe3O4纳米颗粒与硬脂酸分子在空气/水界面形成的朗缪尔单层及其稳定性。透射电子显微镜和布鲁斯特角显微镜（BAM）研究表明，增加表面压力会导致从纳米颗粒复合物的分离良好的区域转变为压缩良好的单颗粒层。
