Multiscale dynamics of pretransitional fluctuations in the isotropic phase of a lyotropic liquid crystal. Physical review. E, Statistical, nonlinear, and soft matter physics [Phys Rev E Stat Nonlin Soft Matter Phys] Journal article | | Title | Multiscale dynamics of pretransitional fluctuations in the isotropic phase of a lyotropic liquid crystal. | | Author(s) | Bertrand CE, Linegar KL, Kostko AF, Anisimov MA | | Institution | Department of Chemical and Biomolecular Engineering and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA and Department of Chemical Engineering, The Petroleum Institute, Abu Dhabi, P.O. Box 2533, United Arab Emirates. | | Source | Phys Rev E Stat Nonlin Soft Matter Phys 2009 Apr; 79(4-1):041704. | | Abstract | Using an improved static and dynamic light-scattering technique, we have observed multiscale relaxation of the pretransitional fluctuations in the isotropic phase of a cromolyn aqueous solution, a lyotropic liquid crystal where rods are formed by aggregates of disklike molecules. We have detected the onset of cromolyn aggregation about 12 degrees C above the transition temperature. The onset is manifested by the emergence of strong scattering due to the fluctuations of local anisotropy and by the split of the diffusion dynamics into two distinctly different modes, one associated with the relatively fast diffusion of monomer-size particles and the other one with the much slower diffusion of the cromolyn aggregates. A third observed dynamic mode is associated with the pretransitional slowing down of fluctuations of the local anisotropy. This mode behaves differently in polarized and depolarized light scattering, due to a coupling between fluctuations of the local-anisotropy and velocity fluctuations. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19518247 |
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