Department of Materials Science, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake City, Kolkata 700 098, India.
Langmuir. 2011 Apr 5;27(7):3930-6. doi: 10.1021/la104306m. Epub 2011 Mar 3.
A monolayer of dodecanethiol-encapsulated Au nanoparticles when compressed laterally transforms into layer-by-layer assemblies on water surface. These layer-by-layer assemblies of Au nanoparticles have been deposited on H-terminated Si(001) substrates by using one down-up cycle (two strokes) in the Langmuir-Blodgett (LB) method. The transformation from monolayer to layer-by-layer assembly on a water surface is irreversible; i.e., if the compressed film is decompressed the layer-by-layer structure cannot regenerate the monolayer structure. Unlike layer-by-layer growth, only odd numbers of layers grow from the monolayer on the H-terminated Si(001) substrates by using different numbers of down-up cycles. Z-type LB deposition occurs only in the first down-up cycle of the hydrophobic substrate, whereas Y-type LB deposition takes place in the successive cycles. Such layer-by-layer assemblies of Au nanoparticles, which are made on bare silicon surfaces and where thickness can be controlled at the nanoscale level, are very promising for their novel applications in the field of nanoscience.
当单层十二硫醇包裹的金纳米粒子被横向压缩时，会在水表面上转化为层层组装体。这些金纳米粒子的层层组装体已通过 Langmuir-Blodgett (LB) 方法中的一个上下循环（两次冲程）沉积在 H 终止的 Si(001) 衬底上。在水表面上从单层到层层组装的转变是不可逆的；也就是说，如果压缩的薄膜被减压，层层结构就无法再生单层结构。与层层生长不同，只有奇数层可以从 H 终止的 Si(001) 衬底上的单层通过使用不同数量的上下循环生长。Z 型 LB 沉积仅发生在疏水衬底的第一个上下循环中，而 Y 型 LB 沉积则发生在连续的循环中。在裸硅表面上形成的这种金纳米粒子的层层组装体，其厚度可以在纳米尺度上控制，在纳米科学领域具有非常广阔的应用前景。
