Reproducibility of known Auto Paints

Step two for my research over the summer is reproducibility of known auto paints from a collision center. These are not actual auto paints samples from the manufacturer but paints used by the collision center to match the manufactured paint. Over the past semester, we had identified a specific Raman spectrum using surface-enhanced Raman spectroscopy for a particular paint. My goal was to simply reproduce this spectrum. Reproducing something is often much harder then it sounds unfortunately. After much trial and error, I was able to reproduce the spectrum on multiple samples on different days. Success! I was also able to reproduce the spectrum of the other paints provided by the collision center. Through the reproduced spectra, I was also able to prove that the chromophore or pigment used by the specific collision center was the same for all the paints. Double-success! Step three is to obtain an identifiable spectrum from auto paints actually from the manufacturer.

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Have you ever watched colloids dry?

At the beginning of the summer I developed a series of steps that I need to complete in order to have a successful summer researching auto paints. The first step was stabilizing the colloidal silver nanoparticles that my lab uses; we call them colloids for simplicity. Colloids are a suspension of silver nanoparticles in a sodium citrate and water solution. Stable colloids can be applied to auto paint samples, amongst other substances, for surface-enhanced Raman spectroscopy analysis. The trick is getting them to remain stabilized. Over the past semester, our colloids were only stable for a max of two days. The lifespan of colloids should be upwards of two weeks. After reviewing the procedure that we had been using all semester, we found some flaws. We discovered that our sodium citrate was expired by three years and that we were not boiling the silver nitrate enough before adding the sodium citrate. We corrected these two details and now we have colloids that last for three weeks! With stabilized colloids, I am able to move on to step two, reproducibility of auto paint standards.

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