Title: Coordination number distribution in colloidal suspensions and emulsions

Author (Invited): Jasna Brujic, Columbia University

Abstract:

Pouring sugar into a cup is the simplest example of a fluid to solid transition which takes place solely because of an increase in particle density, identified as the jamming transition. In other words, if the particle density is high enough to support an external weight without the constituent grains starting to flow and rearrange, the material has the properties of a solid and is known to be at the isostatic limit. This state arises when the particles have enough contacts between them such that all the forces balance according to Newton's equations. The average number of contacts per particle, , known as the coordination number, is therefore the key parameter that determines the mechanical properties of granular materials. Theory predicts that a system of smooth particles has a minimal average number of contacts for mechanical stability =2D, where D is the dimension of the system.