These flasks all contain the same amount of a fluorescent napthalimide dye. Why aren’t they all glowing at the same intensity? Water. From left to right, the flasks contain increasing amounts of water. At first, upping the water content from 0% to 10%, and thus decreasing the amount of organic solvent, turns off the dye’s glow (first two flasks from left). Trinity College Dublin graduate student Adam Henwood and professor Thorri Gunnlaugsson designed this naphthalimide dye to form nanoparticles that glow even brighter than the free-floating molecules. As the water content rises to 95% (far right), the hydrophobic dye molecules bunch up to form these particles and the flask’s glow intensifies.
Submitted by Adam Henwood and Thorri Gunnlaugsson
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