'Colloidal gels,' ubiquitous in everyday products, divulge their secrets
Researchers at MIT have developed a new method for determining the structure and behavior of a class of widely used soft materials known as weak colloidal gels, which are found in everything from cosmetics to building materials. The study characterizes the gels over their entire evolution, as they change from mineral solutions to elastic gels and then glassy solids.
The work uncovers the microstructural mechanisms underlying how the gels change naturally over time, and how their elastic properties also change, both over time and depending on the rate at which they are experimentally deformed. This characterization should allow further study, prediction, and perhaps manipulation of the gels' behavior, opening doors to advances in such areas as drug delivery and food production, in which these gels are common ingredients, as well as in applications ranging from water purification to nuclear waste disposal, which use these colloidal gels in a crystallized, porous form known as zeolites.
"We believe this new overall picture and understanding of the gelation and subsequent aging process is of great importance for material scientists who work on soft matter," says Gareth McKinley, the School of Engineering Professor of Teaching Innovation and professor of mechanical engineering at MIT.