Editing Colloid (section)

===Accelerating methods for shelf life prediction===
The kinetic process of destabilisation can be rather long (up to several months or years for some products). Thus, it is often required for the formulator to use further accelerating methods to reach reasonable development time for new product design. Thermal methods are the most commonly used and consist of increasing temperature to accelerate destabilisation (below critical temperatures of phase inversion or chemical degradation). Temperature affects not only viscosity, but also interfacial tension in the case of non-ionic surfactants or more generally interactions forces inside the system. Storing a dispersion at high temperatures enables to simulate real life conditions for a product (e.g. tube of sunscreen cream in a car in the summer), but also to accelerate destabilisation processes up to 200 times.
Mechanical acceleration including vibration, [[centrifugation]] and agitation are sometimes used. They subject the product to different forces that pushes the particles / droplets against one another, hence helping in the film drainage. Some emulsions would never coalesce in normal gravity, while they do under artificial gravity.<ref>{{cite book|url=https://books.google.com/books?id=hDOS5OfL_pQC&pg=PA89|page=89|author= Salager, J-L |title=Pharmaceutical emulsions and suspensions|editor1=Françoise Nielloud |editor2=Gilberte Marti-Mestres |year=2000|isbn=978-0-8247-0304-2|publisher=CRC press}}</ref> Segregation of different populations of particles have been highlighted when using centrifugation and vibration.<ref>{{cite journal|doi=10.1021/la802459u|title=Size Segregation in a Fluid-like or Gel-like Suspension Settling under Gravity or in a Centrifuge|year=2008|last1=Snabre|first1=Patrick|last2=Pouligny|first2=Bernard|journal=Langmuir|volume=24|pages=13338–47|pmid=18986182|issue=23}}</ref>