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The self and collective diffusion in complex fluids is studied within a dynamic
density functional theory which explicitly accounts for the coupling to the
fluctuating background [1]. Applying the formalism to nematic and smectic
liquid crystals, the formation of temporary cages by neighbouring particles is
found to compete with permanent barriers in nonuniform systems, resulting in
non-Gaussian diffusive motion that in different directions becomes correlated
[1]. String-like clusters formed by particles from adjacent smectic layers are
found to diffuse collectively [1], which has recently also been observed by
means of computer simulations [2]. Qualitative agreement with experiments [3]
demonstrates the importance of explicitly dealing with time-dependent
self-consistent molecular fields.
[1] M. Bier, R. van Roij, M. Dijkstra, and P. van der Schoot: Phys. Rev. Lett. 101, 215901 (2008) [2] A. Patti, D. El Masri, R. van Roij, and M. Dijkstra: J. Chem. Phys. 132, 224907 (2010) [3] E. Grelet, M.P. Lettinga, M. Bier, R. van Roij, and P. van der Schoot: J. Phys.: Condens. Matter 20, 494213 (2008) |
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