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Tangential Flow Ultrafiltration: A “Green” Method for the Size Selection and Concentration of Colloidal Silver Nanoparticles
Published on: October 4, 2012
Time-resolved and steady state spectroscopy of polydisperse colloidal silver nanoparticle samples
Min Hu1, Hristina Petrova, Xuan Wang
1Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, USA.
The Journal of Physical Chemistry. B
|July 21, 2006
Summary
Coherent vibrational motion was detected in silver nanoparticles. Analysis revealed that triangular silver nanoparticles, not spheres or rods, generated this signal, with vibration period dependent on particle size.
Area of Science:
- Nanotechnology
- Materials Science
- Physical Chemistry
Background:
- Silver nanoparticles exhibit unique optical and electronic properties.
- Understanding nanoparticle vibrational dynamics is crucial for applications in sensing and catalysis.
- Previous studies have explored nanoparticle vibrations, but attribution to specific shapes remains challenging.
Purpose of the Study:
- To investigate coherently excited vibrational motion in polydisperse silver nanoparticle samples.
- To determine the contribution of different silver nanoparticle shapes (spheres, rods, triangles) to the observed vibrational signal.
- To correlate the vibrational periods with particle dimensions and material properties.
Main Methods:
- Synthesis of polydisperse silver nanoparticles using wet chemistry seed-mediated method.
- Observation of coherently excited vibrational motion.
- Comparison of experimental vibrational periods with continuum mechanics calculations.
- Analysis of particle morphology, including spheres, rods, and irregular triangles.
Main Results:
- A distinct signal attributed to coherently excited vibrational motion was observed.
- The vibrational signal was definitively linked to triangular-shaped silver nanoparticles.
- A quantitative relationship was established: vibrational period increases with the size (bisector length, h) of triangular nanoparticles, following the formula 2h/c(l), where c(l) is the longitudinal speed of sound in silver.
Conclusions:
- Triangular silver nanoparticles are responsible for the observed coherently excited vibrational motion.
- The vibrational period of these triangular nanoparticles is size-dependent and predictable via a derived formula.
- This finding advances the understanding of vibrational dynamics in anisotropic nanoparticles and their characterization.
