Journal Article

FZJ-2015-00549

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Electric-field induced microdynamics of charged rods

Kang, K. (Corresponding Author)FZJ*

2014
Frontiers Media Lausanne

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Please use a persistent id in citations: http://hdl.handle.net/2128/8386  doi:10.3389/fphy.2014.00073

Abstract: Electric-field induced phase/state transitions are observed in AC electric fields with small amplitudes and low frequencies in suspensions of charged fibrous viruses (fd), which are model systems for highly charged rod-like colloids. Texture- and particle-dynamics in these field-induced states, and on crossing transition lines, are explored by image time-correlation and dynamic light scattering, respectively. At relatively low frequencies, starting from a system within the isotropic-nematic coexistence region, a transition from a nematic to a chiral nematic is observed, as well as a dynamical state where nematic domains melt and reform. These transitions are preliminary due to field-induced dissociation/association of condensed ions. At higher frequencies a uniform state is formed that is stabilized by hydrodynamic interactions through field-induced electro-osmotic flow where the rods align along the field direction. There is a point in the field-amplitude vs. frequency plane where various transition lines meet. This point can be identified as a “non-equilibrium critical point,” in the sense that a length scale and a time scale diverge on approach of that point. The microscopic dynamics exhibits discontinuities on crossing transition lines that were identified independently by means of image and signal correlation spectroscopy.

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Contributing Institute(s):

1. Weiche Materie (ICS-3)

Research Program(s):

1. 451 - Soft Matter Composites (POF2-451) (POF2-451)

Appears in the scientific report 2014

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