Rheological Behavior of Shear Thickening Fluids

Shear thickening fluids are dense suspensions that exhibit a striking increase in viscosity when subjected to applied stress or shear rate. At rest or under gentle flow these materials behave like low‐viscosity liquids, but as the shear rate exceeds a critical threshold they develop transient structures—often termed hydroclusters—leading to dramatic stiffening or even solid‐like response. The underlying mechanisms encompass both hydrodynamic forces and direct particle–particle contacts, with frictional interactions playing a pivotal role in discontinuous shear thickening and shear jamming. Advances in imaging and microrheology have revealed that stress‐activated frictional contacts can nucleate jamming fronts that propagate through the material without significant densification. Such behaviour underpins a wide spectrum of applications, from impact‐absorbing protective gear and adaptive damping systems to novel electrolytes for energy storage. Control over particle surface properties, volume fraction and interstitial fluid chemistry now permits tunable responses, enabling the design of smart fluids that switch rapidly between fluid and solid states under demand.

Research from Nature Portfolio

Recent studies have quantified the nanoscale frictional profile between particles, demonstrating that a transition from hydrodynamic lubrication to hard repulsive contact occurs at a normal stress matching the macroscopic onset of discontinuous shear thickening. Experimental probes combining atomic‐force microscopy with macroscopic rheometry have bridged length scales and confirmed that stress‐activated frictional forces govern the viscosity jump. Complementary work using temperature‐responsive coatings on colloidal particles has shown that one can reversibly tune adhesive and frictional interactions in situ, thereby switching discontinuous shear thickening on and off. High‐speed ultrasound imaging has further revealed that dynamic shear jamming under impact proceeds via anisotropic jamming fronts, providing direct evidence that shear, rather than densification, drives solidification in dense suspensions.

Rheological Behavior of Shear Thickening Fluids publication trend

The graph below shows the total number of articles in rheological behavior of shear thickening fluids across all publications each year (not limited to Nature Index journals).

Technical terms

Shear thickening: The phenomenon by which a fluid’s viscosity increases with increasing shear rate or stress.

Hydrocluster: A transient aggregate of particles formed under shear due to hydrodynamic interactions.

Discontinuous shear thickening: An abrupt, often orders‐of‐magnitude, jump in viscosity occurring at a critical shear stress.

Shear jamming: A stress‐induced transition from a flowing suspension to a solid‐like, yield‐stress state without significant change in packing fraction.

Frictional contact: Direct particle–particle interaction dominated by surface friction that arises once hydrodynamic lubrication layers break down under stress.

References

1. Pairwise frictional profile between particles determines discontinuous shear thickening transition in non-colloidal suspensions. Nature Communications (2017).
2. Exploring the roles of roughness, friction and adhesion in discontinuous shear thickening by means of thermo-responsive particles. Nature Communications (2021).
3. High-speed ultrasound imaging in dense suspensions reveals impact-activated solidification due to dynamic shear jamming. Nature Communications (2016).
4. Shear thickening fluid (STF) in engineering applications and the potential of cork in STF-based composites. Advances in Colloid and Interface Science (2024).
5. Capillary-Stress Controlled Rheometer Reveals the Dual Rheology of Shear-Thickening Suspensions. Physical Review X (2023).
6. Polyethylene Oxide (PEO) Provides Bridges to Silica Nanoparticles to Form a Shear Thickening Electrolyte for High Performance Impact Resistant Lithium‐ion Batteries. Advanced Science (2023).