Self-diffusiophoretic spheroid in a shear-thinning fluid*

Shear-thinning viscosity is a non-Newtonian behavior commonly found in biological fluids like blood and mucus. Its impact on the propulsion of active particles has garnered significant interest. It was shown that spherical Janus particles driven by self-diffusiophoresis always swim slower in a shear-thinning fluid than in a Newtonian fluid. In this talk, we move beyond the spherical limit to discuss the effect of particle geometry on self-diffusiophoretic propulsion in a shear-thinning fluid. Via asymptotic analysis and numerical simulations, we demonstrate that shear-thinning rheology can enhance the propulsion of spheroidal particles, in contrast to previous findings for spherical particles. We also present symmetry arguments to elucidate some new features emerging from the combined effect of anisotropy of the spheroidal geometry and nonlinear fluid rheology.