Editing Colloid (section)

== Interaction between particles ==
The following forces play an important role in the interaction of colloid particles:<ref name="Lekkerkerker">{{cite book| last1=Lekkerkerker| first1=Henk N.W.| last2=Tuinier| first2=Remco| title=Colloids and the Depletion Interaction| publisher=Springer| location=Heidelberg| date=2011| doi=10.1007/978-94-007-1223-2| isbn=9789400712225| url=https://cds.cern.ch/record/1399210| access-date=5 September 2018| archive-url=https://web.archive.org/web/20190414163235/https://cds.cern.ch/record/1399210| archive-date=14 April 2019| url-status=dead}}</ref><ref name="vanAndersPNAS2014">{{cite journal|last1=van Anders| first1=Greg| last2=Klotsa| first2=Daphne| last3=Ahmed| first3=N. Khalid| last4=Engel| first4=Michael| last5=Glotzer| first5=Sharon C.| date=2014| title=Understanding shape entropy through local dense packing|journal=Proc Natl Acad Sci USA|volume=111| issue=45|pages=E4812–E4821|doi=10.1073/pnas.1418159111|arxiv=1309.1187| pmid=25344532| pmc=4234574|bibcode=2014PNAS..111E4812V| doi-access=free}}</ref>
*[[Excluded volume|Excluded volume repulsion]]: This refers to the impossibility of any overlap between hard particles.
*[[Coulomb's law|Electrostatic interaction]]: Colloidal particles often carry an electrical charge and therefore attract or repel each other. The charge of both the continuous and the dispersed phase, as well as the mobility of the phases are factors affecting this interaction.
*[[van der Waals force]]s: This is due to interaction between two dipoles that are either permanent or induced. Even if the particles do not have a permanent dipole, fluctuations of the electron density gives rise to a temporary dipole in a particle. This temporary dipole induces a dipole in particles nearby. The temporary dipole and the induced dipoles are then attracted to each other. This is known as van der Waals force, and is always present (unless the refractive indexes of the dispersed and continuous phases are matched), is short-range, and is attractive.
*[[Steric effects|Steric forces]]: A repulsive steric force typically occurring due to adsorbed polymers coating a colloid's surface. 
*[[Depletion force|Depletion forces]]: An attractive entropic force arising from an osmotic pressure imbalance when colloids are suspended in a medium of much smaller particles or polymers called depletants.