On Sweat and Hair Gel: A Match Made Somewhere Other Than Heaven

Many hair gels, hand sanitizers, and other consumer products are formulated with a yield stress, which is achieved using microgel particles that swell and crowd into a jammed state.  This swollen state is essential for the rheological and aesthetic properties of the product.  Here we demonstrate rather dramatic phenomena that can be achieved when microgel particles are driven to collapse — a macroscopically visible manifestation of the meso-scopic structure of the material.  Demonstrations will be provided.