Capillary suspensions: Particle networks formed through the capillary force

• Published in: Current opinion in colloid & interface science Vol. 19; no. 6; pp. 575 - 584
• Main Author: Koos, Erin
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2014
• Subjects: Bridging; Capillarity; Capillary suspensions; Clusters; Colloidal clusters; Colloids; Fluid dynamics; Fluid flow; Fluids; Network formation; particle physics; Percolation; research methods; rheological properties; Ternary systems; Capillary suspensions; Percolation; Colloidal clusters; Ternary systems; Capillary force
• ISSN: 1359-0294; 1879-0399
• DOI: 10.1016/j.cocis.2014.10.004

The addition of small amounts of a secondary fluid to a suspension can, through the attractive capillary force, lead to particle bridging and network formation. The capillary bridging phenomenon can be used to stabilize particle suspensions and precisely tune their rheological properties. This effect can even occur when the secondary fluid wets the particles less well than the bulk fluid. These materials, so-called capillary suspensions, have been the subject of recent research studying the mechanism for network formation, the properties of these suspensions, and how the material properties can be modified. Recent work in colloidal clusters is summarized and the relationship to capillary suspensions is discussed. Capillary suspensions can also be used as a pathway for new material design and some of these applications are highlighted. Results obtained to date are summarized and central questions that remain to be answered are proposed in this review. [Display omitted] •Immiscible fluid added to suspensions can cause network formation and gelation.•Phenomenon exists even when wetting of particles by secondary fluid is unfavorable.•Agglomeration controlled by tunable capillary force, mixing conditions and history•Possible applications include porous ceramics, li-ion batteries and low-fat foods.