Probing microscopic wiggles in squishy materials
The term “colloidal gel” may not be a household name, but examples of these materials are everywhere in our daily lives, from toothpaste and shower gel to mayonnaise and yogurt. Colloidal gels are mixtures of particles suspended in fluid, and depending on how they are manipulated, these gels can flow like liquid or hold their shape like a solid. Now MIT researchers have peered into the microstructure of colloidal gels and identified a surprisingly rich variety of behaviors in these squishy, phase-defying materials. The team captured movies of colloidal gels as they formed, starting as individual particles in water and evolving into thick, uniform goo. The researchers zoomed in at various size scales to observe any activity in the morphing material, and discovered a range of scale-dependent behaviors. The researchers say their findings, reported on Feb. 27 in the journal Physical Review Letters, represent the first comprehensive study of the microstructure of colloidal...