Colloids (or suspended particles) are all around us. Examples of colloids include aerosols, emulsions, and nanoparticles (NPs) in the size range of 10–9 to 10–6 m. At this length scale, particle surface area to volume ratio is large. Thus, colloidal surfaces play a central role in chemical processes relevant to nanotechnology and environmental sciences. In the recent decades, second harmonic generation (SHG) spectroscopy has shown to be useful in probing colloidal surfaces in situ. However, challenges and limitations still exist when the colloidal mixture is complex. In this presentation, experimental work predominantly conducted by undergraduate students will be showcased. Two distinct chemical processes, dye-induced aggregation of magnetic particles (MPs) and enhanced photochemical reactivity of an organic dye at the surface of polymeric microsphere will be highlighted. It will be shown that a synergistic combination of SHG and traditional spectroscopic measurements can yield valuable information about the molecular interaction with different types of particle surfaces. The impact of the findings will be discussed in the context of fundamental surface science and practical aspects relevant to pollution remediation and photo-degradation of organic contaminants in the aquatic environment.

Shedding light on colloidal surfaces: Exposing molecular behavior and chemical reactivity at the solid-liquid interface

254th National Meeting (2017)

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