Journal of Nanomedicine & Nanotechnology

Size is relative: When is a charged sphere small enough to be considered a point charge, and large enough to be considered a charged plane?

4^th International Conference on Nanotek & Expo

December 01-03, 2014 DoubleTree by Hilton Hotel San Francisco Airport, USA

Ho-Kei Chan, Eric B. Lindgren, Anthony J Stace and Elena Bichoutskaia

Posters: J Nanomed Nanotechnol

Abstract:

A geometric parameter is derived from the bispherical coordinate system to describe geometries of electrostatic spheresphere interactions, such as those among water droplets and among colloidal particles. At short separation distances where the dimensions of the spheres become important, attraction can occur between two like-charged, polarizable spheres, where such attraction is not described by Coulomb?s law for a pair of point charges. Taking into account the sizes of the spheres, this parameter serves as a geometric measure of how good it is to approximate the system as a pair of point charges, and it provides a geometric understanding of the system?s deviation from Coulomb?s law. The parameter provides a unified geometric description not only for cases of finite-sized spheres, but also for cases that involve a point charge, i.e. an infinitesimally small sphere or a charged plane, i.e. an infinitely large sphere.

Biography :

Ho-Kei Chan has developed a method of sequential deposition for constructing the densest possible cylindrical packings of equal-sized spheres. He obtained a 1st class degree in Engineering Physics (2002) from the Hong Kong Polytechnic University and a PhD in Nonlinear and Liquid Crystal Physics (2007) from the University of Manchester, followed by post-doctoral research in Hong Kong, Ireland and England. He has published in various areas of soft matter physics and physical chemistry.