Bridging the gap from active suspensions in Newtonian fluids to active nematics

Active particles in anisotropic, viscoelastic environments can trigger a bend instability, but the pursuant flow can be arrested by elastic fluid stresses. We will discuss a model active suspension in a nematic LC, and explore the initial stages of this instability from the distribution function perspective. Of particular interest is the role of the anchoring strength, which links the active and passive media, and tunes the system between active suspensions in Newtonian fluids in one limit and active nematic theory in another. A base state is identified that reveals an intriguing and delicate competition between the anchoring strength and the particle rotational diffusivity. This state transitions from an isotropic configuration at zero anchoring strength to a strongly aligned one in the limit of large anchoring strength. The effect of anchoring strength can be divided into two parts: the anisotropy of the base state enhances instability, whereas the alignment tends to stabilize the suspension.