Raman Vibrational Evidence for the Presence of Conjugated Regions in Individual Micron Diameter Polystyrene Particles Irradiated with Visible Radiation

• Published in: The journal of physical chemistry. B Vol. 102; no. 13; pp. 2325 - 2328
• Main Authors: Crawford, Kevin D, Hughes, Kenneth D
• Format: Journal Article
• Language: English
• Published: American Chemical Society 26.03.1998
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp972462d

Micron diameter particles containing or composed solely of polystyrene have been reported to become highly fluorescent shortly after immobilization in a visible optical trap (488.0 nm). It has been proposed that extensive regions of conjugation in the polymer backbone are responsible for this emission. Raman spectroscopic evidence is described in this report that confirms the presence of polymer backbone conjugation. In some experiments Raman signals were enhanced by incorporating silver nanoparticles into the micron-diameter polystyrene particles by photoreduction of silver ion. By monitoring the intensity changes of the C−H and CC stretching regions while an individual particle is immobilized in the optical trap, the generation of extensive conjugation regions can be observed over time. In addition, the presence of the silver nanoclusters increased the rate and magnitude of the reactions that lead to polystyrene conjugation.