When you mix cornstarch and water you get an unusual result. If you treat it gently, it behaves like a liquid. But if you are rough with it, it behaves like a solid. How can this be? Itai Cohen, associate professor of physics, and his graduate student, Neil Lin, demonstrate the phenomenon and explain the reasons behind it.
Fascinating rheological properties like shear thickening/thinning and anisotropic viscosity arise from underlying structure in complex fluids. We develop and use techniques to simultaneously analyze emergent, large-scale properties and image particle-level positions and stresses in such suspensions.
Determining Quiescent Colloidal Suspension Viscosities Using the Green-Kubo Relation and Image-Based Stress Measurements
Microscopy is the workhorse of the physical and life sciences, producing crisp images of everything from atoms to cells well beyond the capabilities of the human eye. However, the analysis of these images is frequently little better than automated manual marking. Here, we revolutionize the analysis of microscopy images, extracting all the information theoretically contained in a complex microscope image.
Did you know that your brighfield or confocal microscope can actually measure stresses in colloidal materials? Here we introduce our SALSA (Stress Assessment from Local Structrure Anisotropy) method determining the stresses in hard-sphere colloidal suspensions. By just using the particle positions, SALSA can effectively transform your micorscope into a local pressure gauge.
Visualization, coarsening, and flow dynamics of focal conic domains in simulated smectic-A liquid crystals
Our shear thickening paper that settles a decades-long debate in suspension rheology has been selected as PRL Editor's Suggestion.