Kaur Prabhjot, Rajput Jaspreet Kaur, Singh Kultar, Khullar Poonam, Bakshi Mandeep Singh
Department of Chemistry, Natural and Applied Sciences, University of Wisconsin-Green Bay, 2420 Nicolet Drive, Green Bay, Wisconsin 54311-7001, United States.
Department of Chemistry, B.B.K. D.A.V. College for Women, Amritsar 143005, Punjab, India.
Langmuir. 2022 Jun 28;38(25):7802-7814. doi: 10.1021/acs.langmuir.2c00853. Epub 2022 Jun 16.
Ag and Au nanoparticles (NPs) were used as color indicators to determine the monomer/micelle adsorption on the NP surface. A simple methodology based on the color change of Ag/Au NPs upon interacting with surface-active molecules was developed. A contrasting color change occurred when NPs interact with the monomer/micelle. This was demonstrated by monitoring the adsorption behavior of a series of Gemini surfactants. UV-visible measurements showed a large change in the intensity and wavelength of Ag/Au NP absorbance upon the surface adsorption of the monomer/micelle of Gemini surfactants. The mechanism of surface adsorption and molecular orientation on the solid-liquid interface of NPs was determined by performing the FT-IR and XPS measurements. Results demonstrated that sharp color changes from yellow to red for Ag NPs and red to purple for Au NPs happened when the Gemini surfactant monomer/micelle adsorbs on the NP surface. This colorimeter-based methodology highlighted the applicability of Ag/Au NPs in complex media where such NPs frequently encounter surface-active molecules.
银和金纳米颗粒（NPs）被用作颜色指示剂来确定单体/胶束在NP表面的吸附情况。基于银/金纳米颗粒与表面活性分子相互作用时颜色变化开发了一种简单的方法。当纳米颗粒与单体/胶束相互作用时会发生对比鲜明的颜色变化。通过监测一系列双子表面活性剂的吸附行为证明了这一点。紫外可见测量表明，在双子表面活性剂的单体/胶束表面吸附时，银/金纳米颗粒吸光度的强度和波长发生了很大变化。通过进行傅里叶变换红外光谱（FT-IR）和X射线光电子能谱（XPS）测量确定了纳米颗粒固液界面上的表面吸附和分子取向机制。结果表明，当双子表面活性剂单体/胶束吸附在NP表面时，银纳米颗粒会从黄色急剧变为红色，金纳米颗粒会从红色变为紫色。这种基于比色计的方法突出了银/金纳米颗粒在复杂介质中的适用性，在这种介质中此类纳米颗粒经常会遇到表面活性分子。
