Supersaturated dispersions of rod-like viruses with added attraction

TL;DR

This study investigates the phase transition kinetics in dispersions of rod-like viruses, revealing that attraction influences are minimal on the spinodal points and nucleation parameters when scaled appropriately.

Contribution

It provides the first experimental bifurcation diagram for rod-like virus dispersions and shows attraction effects are negligible on phase transition kinetics when scaled properly.

Findings

N-I spinodal points are unaffected by attraction.

Induction time and nucleus size are insensitive to attraction when scaled.

Constructed the first experimental bifurcation diagram for these dispersions.

Abstract

The kinetics of isotropic-nematic (I-N) and nematic-isotropic (N-I) phase transitions in dispersions of rod-like {\it fd}-viruses are studied. Concentration quenches were applied using pressure jumps in combination with polarization microscopy, birefringence and turbidity measurements. The full biphasic region could be accessed, resulting in the construction of a first experimental analogue of the bifurcation diagram. The N-I spinodal points for dispersions of rods with varying concentrations of depletion agents (dextran) were obtained from orientation quenches, using cessation of shear flow in combination with small angle light scattering. We found that the location of the N-I spinodal point is independent of the attraction, which was confirmed by theoretical calculations. Surprisingly, the experiments showed that also the absolute induction time, the critical nucleus and the growth rate are insensitive of the attraction, when the concentration is scaled to the distance to the phase boundaries.