Department of Chemical Engineering, The City College of New York, NY 10031, USA.
J Colloid Interface Sci. 2013 Mar 15;394:26-35. doi: 10.1016/j.jcis.2012.11.042. Epub 2012 Dec 13.
Adsorption of nanoparticles on solid supports is a scientifically interesting and technologically important phenomenon that has been attracting ever-increasing attention. Formation of particle-based films onto surfaces from stable suspensions is at the center of the development of new devices that utilize the plethora of newly synthesized nanoparticles with exciting properties. In this study we exploit the attractive electrostatic interactions between silica (SiO(2)) nanoparticles and functionalized substrates that display an amine termination in order to devise a simple method for the fabrication of SiO(2) nanoparticle films. Electrostatically controlled adsorption allows for uniform coverage of nanoparticles over large areas. The Stöber method (a sol-gel approach) was employed to prepare uniformly sized SiO(2) nanoparticles with a diameter of 50-80 nm. Native oxide-covered silicon wafer substrates were amino-functionalized utilizing the self-assembled monolayer of 3-aminopropyltrimethoxysilane (APS). The adsorption of SiO(2) nanoparticle film onto the silicon wafer substrate was controlled by modulation of the electrostatic interaction between nanoparticles and the substrate. Modification of surface charge of either the SiO(2) NP or the substrate is a crucial step in the process. Thus the effect of APS adsorption time on the surface energy of the substrate was investigated. Also, process parameters such as NP concentration and solvent composition were varied in order to investigate the extent of NP adsorption. Moreover, NaCl was introduced to the SiO(2) suspension as a charge-screening agent to reduce the inter-particle repulsion in the suspension as well as interaction of the particles with the surface. This resulted in denser/thicker films.
纳米粒子在固体载体上的吸附是一种具有科学趣味性和技术重要性的现象，引起了越来越多的关注。从稳定的悬浮液中将基于粒子的薄膜形成到表面上，是开发利用具有令人兴奋性质的大量新合成纳米粒子的新设备的核心。在这项研究中，我们利用二氧化硅（SiO2）纳米粒子与显示胺端基的功能化基底之间的吸引力静电相互作用，设计了一种简单的方法来制造 SiO2 纳米粒子膜。静电控制的吸附允许在大面积上均匀覆盖纳米粒子。使用Stöber 方法（溶胶-凝胶方法）制备了具有 50-80nm 直径的均匀尺寸的 SiO2 纳米粒子。使用 3-氨丙基三甲氧基硅烷（APS）的自组装单层将天然氧化硅覆盖的硅晶片基底进行氨基功能化。通过调节纳米粒子和基底之间的静电相互作用来控制 SiO2 纳米粒子膜在硅晶片基底上的吸附。SiO2 NP 或基底的表面电荷修饰是该过程的关键步骤。因此，研究了 APS 吸附时间对基底表面能的影响。此外，还改变了 NP 浓度和溶剂组成等工艺参数，以研究 NP 吸附的程度。此外，将 NaCl 引入到 SiO2 悬浮液中作为电荷屏蔽剂，以减少悬浮液中粒子之间的斥力以及粒子与表面的相互作用。这导致了更密集/更厚的膜。
