Coalescence coupled with either coagulation or flocculation in dilute emulsions

Document Type

Article

Publication Date

5-31-2001

Abstract

In current theories, emulsion destabilization is considered as the combined processes of droplet coagulation/flocculation and coalescence. Irreversible aggregation is usually called coagulation, and the term flocculation is used for reversible aggregation. These theories have different conditions of applicability which are not specified. An approximate criterion for discrimination between coalescence coupled with either coagulation or flocculation in dilute emulsions is proposed. Such discrimination is made possible by comparing the characteristic time for coagulation (Smoluchowski time) with that for floc fragmentation (droplet doublet lifetime, τd). As droplet dimension and electrolyte concentration decrease, and the Stern potential increases, τd is reduced and flocculation takes place. The quantity τd enables one to specify the conditions for the two separate cases. The important role of retarded van der Waals forces, screening length and hydration forces in emulsion coalescence is demonstrated.

Identifier

0035979006 (Scopus)

Publication Title

Colloids and Surfaces A Physicochemical and Engineering Aspects

External Full Text Location

https://doi.org/10.1016/S0927-7757(00)00696-8

ISSN

09277757

First Page

223

Last Page

234

Issue

3

Volume

180

Fund Ref

Norges Forskningsråd

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