Wednesday, June 12, 2019

URSP Student Tristan Moon Explores the Formation of Silica Nanoparticles

I was initially interested in doing research related to analytical chemistry, as I thoroughly enjoy calculations and the precision and accuracy required to work with small amounts of chemicals. With this in mind, I spoke to Dr. Hussam about starting research with him. He was interested in exploring the formation of silica nanoparticles Рparticles small enough that not even conventional microscopes can make them out. We decided to test his proven instrumental method on the formation of these particles, known as the Sțber process. This method involves running the reaction in an airtight container. An instrument known as an equilibrium headspace gas chromatographer then takes minute samples from the vapor within the cell and separates out any volatile chemicals within the sample. We could then analyze these chemicals in order to see how the concentrations change over time. From these changes, we can observe many different chemical and physical properties related to these silica nanoparticles. We were actually able to observe something quite unexpected. Several probe chemicals, known as n-alkylbenzenes, were used to help track the formation of the particles. These benzenes feature an increasing number of -CH2 groups attached to a central ring. We noticed that as the number of -CH2 groups increases, the uncertainty in the results increased and the amount of interaction between the benzenes and the silica nanoparticles decreased. We are still looking into the plausible causes for this.
While the instrumental runs are quite important, the most time is actually spent on data calculations. This allows us to find out important values such as the concentration at which the particles form, the equilibrium formed between these particles and the aqueous phase they are located in, and the kinetics for the formation of said products. Several other instruments are used to characterize the presence and size of the particles, though these runs typically only take a few hours, followed by several more hours of analyzing the data for findings.
Overall, this has been an intriguing research experience that I hope to continue to some degree in my graduate studies.