Silver Nanoparticle Surface Enabled Self-Assembly of Organic Dye Molecules
AbstractFluorescence titration of methylene blue, rhodamine B and rhodamine 6G (R6G) by silver nanoparticle (AgNP) all resulted in an initial steep quenching curve followed with a sharp turn and a much flatter quenching curve. At the turn, there are about 200,000 dye molecules per a single AgNP, signifying self-assembly of approximately 36-layers of dye molecules on the surface of the AgNP to form a micelle-like structure. These fluorescence-quenching curves fit to a mathematical model with an exponential term due to molecular self-assembly on AgNP surface, or we termed it “self-assembly shielding effect”, and a Stern-Volmer term (nanoparticle surface enhanced quenching). Such a “super-quenching” by AgNP can only be attributed to “pre-concentration” of the dye molecules on the nanoparticle surface that yields the formation of micelle-like self-assembly, resulting in great fluorescence quenching. Overall, the fluorescence quenching titration reveals three different types of interactions of dye molecules on AgNP surface: 1) self-assembly (methylene blue, rhodamine B and R6G), 2) absorption/tight interaction (tryptamine and fluorescein), and 3) loose interaction (eosin Y). We attribute the formation of micelle-like self-assembly of these three dye molecules on AgNP to their positive charge, possession of nitrogen atoms, and with relatively large and flat aromatic moieties.
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Deng, H.; Yu, H. Silver Nanoparticle Surface Enabled Self-Assembly of Organic Dye Molecules. Materials 2019, 12, 2592.
Deng H, Yu H. Silver Nanoparticle Surface Enabled Self-Assembly of Organic Dye Molecules. Materials. 2019; 12(16):2592.Chicago/Turabian Style
Deng, Hua; Yu, Hongtao. 2019. "Silver Nanoparticle Surface Enabled Self-Assembly of Organic Dye Molecules." Materials 12, no. 16: 2592.
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