Various chiral-mesophases of charged DNA-virus (bacteriophage fd) suspension are found for a model system of interacting DNA-rods at low ionic strength (below 1 mM salt), in which thicker Debye screening length is present in the equilibrium phase behaviors. In particular, above the isotropic-nematic (I-N) coexistence phase, chiral-nematic (N*) phase occurs in an increase of DNA-rod concentration, followed by X-pattern, and helical domains (HD). At far above I-N and N*-transition concentration, the structural glass (SG) exists with an initial caging, and nearby few LTKA (long-time kinetic arrest) states in the phase diagram of rod-concentration and ionic strength [1]. The system has also exhibited an intriguing the replica symmetry breaking (RSB) occurs in X-pattern (with cavity loops), as the “chiral-glass” (CG) at the intermediate rod-concentration, between self-similar replica of low concentration, larger pitch (200 um) length of N*-domain and high-concentration of smaller pitch (about 10 um) for helical domain [2]. Here, in this talk, how these soft glasses of “crowded” charged DNA-rods are responded to the well-defined 3D bulk shear-flow, in terms of their orientation textures, yield-stress and shear-stresses [3-5]. For low shear rates the fracture that transits to a gradient shear-banded flow upon increasing the shear rate, and finally to a uniform flow pattern at high shear rates. These non-uniform flow patterns extending along the gradient direction are superimposed onto rolling Taylor bands extending along the vorticity direction. The thickness of these rolls both depend on the rod concentration as well as the applied shear rate.
References:
1. K. Kang, “Soft-mode of charged chiral fibrous viruses (fd)”, Soft Matter, 12, 6385-6399, 2016.
2. K. Kang, “Chiral glass of charged DNA rods, Cavity loops”, J. Phys. Commun, 5, 065001, 2021.
3. K. Kang, “Response of shear in bulk orientations of charged DNA rods: Taylor- and gradient-banding”, J. Phys. Commun. 5(4) 045011, 2021.
4. J.K.G. Dhont, K. Kang, H. Kriegs, O. Danko, J. Marakakis, and D. Vlassopoulos, “Nonuniform flow in soft glasses of colloidal rods”, Phys. Rev. Fluids. 2, 043301, 2017.
5. D. Parisi, D. Vlassopoulos, H. Kriegs, J. K. G. Dhont, and K. Kang, Underlying mechanism of shear-banding in soft glasses of charged colloidal rods with orientational domains, Journal of Rheology 66, 365, 2022.