Processing and Characterization of Nanoparticle Coatings for Quartz Crystal Microbalance Testing
Lauren F. Greenlee
Nanotechnology as a means for water purification is a rapidly growing field. Nanoparticle systems such as photocatalytic titanium dioxide and reactive zero valent iron are interesting for their versatile degradation properties over a wide range of contaminants. For both systems, the adsorption of contaminants to the nanoparticles surface plays a key role in the contaminant degradation process. Additionally for ZVI, the kinetics of the iron oxidation reaction in water determines the performance and lifetime of this material as a decontaminant. To fully understand these reactions, we need to be able to quantify small mass changes occurring at the nanoparticle surface in real time. This study has evaluated four coating techniques and several processing parameters in order to optimize nanoparticle coatings to obtain accurate and repeatable results when quartz crystal microbalance is used as a tool to measure real time adsorption and reaction at nanoparticle surfaces. Uniform titanium dioxide coatings were produced from 5 %w/v methanol suspension via spin coating. Zero valent iron was applied using a low concentration 0.1 %w/v methanol suspension by spray coating. The application of multiple coatings, rather than an increase in the suspension concentration, proved to be the best method to increase the mass of nanoparticles on the crystal surface. An upper mass threshold was determined to be approximately 75 µg; above this mass, coatings no longer maintained their uniform rigid characteristic and signal from upper resonance harmonics was lost.
Processing and Characterization of Nanoparticle Coatings for Quartz Crystal Microbalance Testing, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/jres.120.001
(Accessed December 3, 2023)