Developing Methodology to Prepare a Nanoparticle Coated Crystal for Infrared Analyses in Order to Specifically Identify Changes to Molecules that Coat the Surface
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Date
2013-05
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The Ohio State University
Abstract
The widespread use of nanomaterials demonstrates a tremendous benefit to society; however, as nanomaterials are inevitably introduced to the environment, it is unknown how their compositions and coating agents alter in different settings and over a prolonged period of time. Coating agents are applied either during or post synthesis to prevent aggregation. Tracking changes to the molecules that coat the surface of nanomaterials is imperative to understanding the inherent risk when nanomaterials are released to the environment. The purpose of my research is to develop a method to prepare a nanoparticle coated crystal for infrared (IR) analyses in order to specifically identify changes to molecules that coat the surface. The two nanomaterials analyzed in this study were hematite and nanosilver. Citrate was the primary coating agent used on both materials. The particles were coated to IR crystals and the coating layers were evaluated under static and dynamic conditions. Variables included coating agent (water, citrate, phthalic acid) and pH. Previously collected data from batch adsorption experiments of citrate and phthalic acid on hematite were used to validate the static system method for hematite. The static experiments successfully detected the adsorption of citrate on the surface of both hematite and nanosilver. The largest issue involved resolving the spectra; specifically, removing the IR absorption of water. This presence of water proved to be an even greater obstacle in the flow-through cell; however, the most successful method involved subtracting water spectra from each component before resolving. No spectra were obtained from silver perhaps due to the silver not adhering to the flow-through cell surface. Significant progress has been made and once the influence of water is removed, these processes should have a vast potential for further research to determine specific changes to nanoparticle surfaces, particularly with the flow-through cell for greater control over variability.
Description
2013 Denman Undergraduate Research Forum Winner, Second Place
Keywords
nanoparticle, infrared spectroscopy, nanosilver, surface chemistry, hematite, nanomaterial