(346f) Properties of Surface-Asymmetric Metal-Decorated Micro- and Nanospheres

     Composite nanostructures have many unusual optical, magnetic and electronic properties. In particular, surface-asymmetric or anisotropic particles present novel orientation dependent synthetic and chemical functionality, which makes them interesting building blocks for fundamental research and new applications.¹ Surface-asymmetric particles also show promise as emulsion stabilizers and are likely to exhibit giant dipole moments.

     Most of the currently used methods to modify particle surfaces such as chemical and physical vapor deposition or beam epitaxy onto templates require elevated temperatures as well as vacuum conditions. In our previous work, we have investigated the combination of partial particle embedment and electroless deposition, leading to an economical and controllable process performed under mild conditions. We have successfully prepared surface asymmetric polymer microspheres (d = 2.4 – 0.5 µm) with silver nanoparticle caps of adjustable size.

     It is important to study and understand the physical and chemical properties of these surface-anisotropic particles before exploring their application. We will report data on the optical behavior of the anisotropic spheres such as UV-vis absorbance, infrared or Raman spectra, and plasmonic properties as well as chemical functionalization of the silver nanoparticles. Further, we will show data on the effect of electric fields on the orientation and assembly of the surface-asymmetric particles in solution.

1. C. Charnay, A. Lee, S. Man, C. E. Moran, C. Radloff, R. K. Bradley, and N. J. Halas J. Phys. Chem. B 2003, 107, 7327-7333.