Abstract: Photocontrol of pH via Doped Conjugated Polymer Nanoparticles

Hello hello!

My name is Aaron Bayles, and I’m a junior at the College. Since the Fall semester of 2014, I have worked in Dr. Harbron’s chemistry lab, investigating a particular set of fluorescent polymer nanoparticles that can release acid into a solution upon irradiation by UV light, and track the amount of acid released by monitoring the change in the nanoparticles’ inherent fluorescence.

A problem we encountered this past year was that as we attempted to release acid from the nanoparticle by irradiating, we’d receive confirmation via fluorescence modulation that the acid had been released, but pH did not change. We believe that separate, negatively charged sites  of the particle would react with the acid before it entered the solution, thereby eliminating any pH-modifying behavior. Hypothetically, by including a coating polymer into our nanoparticles, we could lessen the magnitude of negative charge and prevent this immediate absorption of acid. However until recently, we have not had the proper equipment to test this theory in order to effectively address that problem. Now, we have a Dynamic Light Scattering (DLS) instrument which has the ability to measure the amount of charge around nanoparticles. As a result, we can incorporate coating polymer into the nanoparticles and measure how the surface charge of the nanoparticle changes, so we can use the right amount and type of coating. This is the main focus of my research this summer, in addition to synthesizing new photoreactive dyes that will work as components within the nanoparticle.

I can’t wait to come back this summer and share my findings with all of you!