Dense suspensions can exhibit discontinuous shear thickening (DST) and shear jamming (SJ) in which the suspension experiences a discontinuous jump in viscosity at a critical shear rate. This reversible solidification can be leveraged in a range of applications, including personal protective wear and damping systems. While many different types of conventional suspensions (such as silica in polyethylene glycol or corn starch in water) display DST at high particle volume fractions, regardless of their varying chemical nature, recent research has demonstrated that the jamming transition is impacted by the inherent chemical and physical details of the particles, including particle roughness, shape, and surface chemistry. Most of these studies are carried out using hard nondeformable particles. However, for polymeric particles the elastic modulus depends on temperature and changes by orders of magnitude near the glass transition temperature (). In this work, we investigate the effect that transitioning through of polymer particles has on the shear jamming of their dense suspensions. To explore this concept, we designed a system consisting of crosslinked particles that undergo thermal glass transition near ambient conditions and study the jamming properties at several temperatures. Contrary to conventional systems, the rheology of the suspension displays dramatic temperature dependency and DST can be suppressed when the temperature is much higher than . Through this study, we reveal how the particle affects shear jamming and provide the foundation knowledge of utilizing polymeric particles for switchable jamming systems and impact mitigation.

Impact of glass transition temperature on the shear jamming of polymeric particle suspensions

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.