סמינר לפיזיקה של מערכות ביולוגיות וחומרים רכים: The rapidly expanding thickening universe: critical points, dethickening, superthickening, and meta material liquids
Itai Cohen, Cornell University
Each year, millions of viewers head to YouTube to watch people walk on water. Of course, these people are not actually walking on water: as stress is applied to a suspension of cornstarch in water, the cornstarch particles come close enough to form force chains that are capable of supporting the weight of a person. While these principles help create popular videos, they can be problematic when it comes to efficient processing of industrial suspensions, which in turn has motivated many studies into this fascinating behavior. In this talk I will review what we understand about thickening, discuss universal features of the thickening transition, show how thickening can be tuned by rapid oscillation protocols to breakup or reinforce the force chains, and describe how we are starting to think of using these techniques to create metamaterial liquids whose viscosity arises from the combination of thickened and Newtonian flows.