Overview
Geomaterials, much like living organisms, have evolved over millions of years, developing unique mechanical and transport properties through nature’s architected design. Their microstructure governs important functions such as soil stability, carbon sequestration, groundwater storage, and nutrient delivery. As we seek innovative sustainable materials, the complex composition (colloidal particles, polymers, and microbes) and properties of geomaterials offer inspiration. My research proposes a novel geoinspired engineering approach, combining nature’s design principles with advanced material synthesis, instrumentation, and experimental data-driven learning to develop advanced sustainable soft and living matter, across multiple length scales.
Current and Past Research
My previous research has focused on understanding the effects of multiscale interactions on the soft-living interactions and flow properties of heterogenous dense suspensions.
Doctoral Research. I explored colloidal surface anisotropy as a powerful
tool for engineering flow behavior in dense suspensions. I synthesized model polymer-based colloids with tunable surface roughness and assembled a confocal-rheometer to investigate flow-induced microstructural changes. My work revealed the first experimental 3D sheared structure in particular suspensions, uncovering the structure-property relationships that inform design principles for engineering shear-thickening fluids from nature-inspired materials for shock absorbing applications. By linking nearest-neighbor contacts to shear thickening
rates, I connected the mechanics of dense colloidal suspensions to granular materials by correlating suspension elasticity at zero shear to its “thermal structure” at jamming.
- Shravan Pradeep, Alan Wessel, and Lilian C Hsiao, Hydrodynamic origin for the suspension viscoelasticity in rough colloids, Journal of Rheology (2022).
- Shravan Pradeep, Mohammad Nabizadeh, Alan R Jacob, Safa Jamali, and Lilian C Hsiao, Jamming distance dictates colloidal shear thickening, Physical Review Letters (2021).
- Shravan Pradeep, Lilian C Hsiao, Contact criterion in suspensions of smooth and rough colloids”, Soft Matter (2020).
Postdoctoral Research. My postdoctoral research was focused on two areas: (i) multiscale soft matter mechanics of heterogenous geomaterials and (ii) emergent dynamics in living systems
Heterogenous Soft Matter Mechanics. I developed a framework to explain the flow and failure behavior of soft particulate materials by decoupling the interparticle interactions and the intrinsic mechanics. This led to discovering rheological constitutive equation with a novel material-controlled brittle-ductile transition that connects granular materials to gels. The geoinspired framework offers insights for designing multiphase soft matter systems, e.g. lithium-ion battery slurries. We further modified the framework by adding soft tribology, and applied to sustainable geomaterials, revealing how the unique balance of cohesive, frictional, and viscous elements in baseball rubbing mud creates a soft material with unusual gripping properties.
- Shravan Pradeep, Xiangyu Chen, Ali Seiphoori, David R Vann, Paulo E Arratia, Douglas J Jerolmack, "Soft matter mechanics of baseball's rubbing mud", PNAS, In Press (2024).
- Shravan Pradeep, Paulo E. Arratia, Douglas J. Jerolmack, Origins of complexity in rheology of Soft Earth suspensions", Nature Communications (2024).
- Ranjiangshang Ran, Shravan Pradeep, Sebastien Kosgodagan Acharige, Brendan Blackwell, Christoph Kammer, Douglas J Jerolmack, and Paulo E Arratia, Understanding the rheology of kaolinite clay suspensions using Bayesian inference, Journal of Rheology (2023).
- Robert Kostynick¶, Hadis Matinpour¶, Shravan Pradeep¶, Thomas Dunne, Sarah Haber, Alban Sauret, Eckart Meiburg, Paulo E Arratia, and Douglas J Jerolmack, Rheology of debris flows controlled by the distance from jamming, PNAS (2022).
Living matter-induced transport. I used colloidal tracers dispersed in E. coli suspensions as model active-passive systems, and decoupled the effects of the geometry and bacterial concentration on tracer dispersal. Through collaborations, we discovered the emergence of bioconvection as function of bacterial concentration, which enhances mixing. These findings
provide insights into microbe-mediated mixing in nature and industrial applications.
- Shravan Pradeep, Nandish Vora, Ranjiangshang Ran, Paulo Arratia, "Stretching field statistics in time-periodic flows with dilute bacterial suspensions", In Preparation.
- Bryan O. Torres Maldonado, Shravan Pradeep, Ranjiangshang Ran, Douglas Jerolmack, Paulo E. Arratia, Sedimentation dynamics of passive particles in dilute bacterial suspensions: emergence of bioconvection, Journal of Fluid Mechanics, (2024).
- Bryan O. Torres Maldonado, Ranjiangshang Ran, K. Lawrence Galloway, Quentin Brosseau, Shravan Pradeep, Paulo E. Arratia, Phase-separation during sedimentation of dilute bacterial suspensions, Physics of Fluids, (2022).