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 – particles 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 Stöber 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.
