Plasmonic Evolution and Arrested Development for Silver Nanoscale Colloids: A Classroom Demonstration

• Jason A. Thon ^[1] ; Nathaniel E. Larm ^[1] ; Yahor Vazmitsel ^[1] ; Gary A. Baker ^[1]
  1. [1] University of Missouri

     University of Missouri

     Township of Columbia, Estados Unidos

     
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 96, Nº 11, 2019, págs. 2560-2564
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • A vivid demonstration visualizing the colloidal behavior of silver nanocrystals is described. An aqueous–ethanol silver ion solution becomes yellow upon initial chemical reduction (using sodium borohydride, NaBH4), which is followed by chromatic evolution to orange, red, violet, and finally blue over the course of approximately 3 min because of the predictable growth and evolution of the nanocrystals. This undergraduate-level classroom demonstration is useful for illustrating the protective effect of a passivating ligand, such as polyvinylpyrrolidone (PVP), by showing the ability of PVP to halt the growth and coalescence of silver colloids at a desired stage, arresting the color transition at a particular hue. This demonstration can also be extended to highlight the bifurcated impact of such passivation on colloid behavior (e.g., improved long-term colloid stability coupled with worsened nanocatalytic performance).