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SUMMARY:Orientational ordering and self-organisation of nanoparticles in l
 iquid crystal and polymer nanocomposites - Mikhail Osipov (University of S
 trathclyde)
DTSTART:20190514T154000Z
DTEND:20190514T160000Z
UID:TALK124420@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:Nematic liquid crystals (LCs) and block copolymers doped with 
 nanoparticles possess a number of interesting properties. In particular\, 
 anisotropic nanoparticles are orientationally ordered in the boundary regi
 on between the blocks [1-3] and a small concentration of nanoparticles can
  shift the transition temperatures between different phases\, orientationa
 l ordering of nanoparticles is responsible for the enhanced dielectric ani
 sotropy of the composite lamellae and hexagonal phases which opens a possi
 bility to align block copolymers by external fields. This may enable one t
 o solve various application problems. We first summarise the results of a 
 molecular theory of nematic LCs doped with anisotropic nanoparticles and d
 escribe the effect of nanoparticles on the N-I phase transition\, the nema
 tic order parameter and consider the formation of chains of polar nanopart
 icle [4-7]. We then present the results of a molecular theory of the induc
 ed orientational order of anisotropic nanoparticles in the lamellae and in
  the hexagonal phase of a diblock copolymer taking into anisotropic intera
 ction between nanoparticles and the polymer chains. Numerical concentratio
 n and orientational order parameter profiles are presented for different v
 alues of the model parameters including the strength of the anisotropic in
 teraction. We also present the results of the general mean-field theory wh
 ich enables one to describe both the effect of segregation of monomers bet
 ween different blocks on the orientational order of nanoparticles and the 
 effect of nanoparticles on the stability of different phases..<br> Finally
  we present the results of the computer simulations of the lamellae and he
 xagonal copolymer nanocomposites doped with nanoparticles of different len
 gth and affinity\, and the simulated concentration and order parameter pro
 files are compared with theoretical results [1\,3]. We also discuss the co
 rresponding phase diagrams which illustrate how the nanoparticles may effe
 ct the phase behaviour of block copolymers.<br> References<br> [1] Osipov\
 , M. A.\, Gorkunov\, M. V.\, Berezkin\, A. V.\, Kudryavtsev\, Y. V.\, Phys
 . Rev. E\, 97\, 042706 (2018) <br> [2] M.A. Osipov and M.V. Gorkunov\, Eur
 .Phys.J.\, 39\, 126 (2016) <br> [3] A.V. Berezkin\, Y.V. Kudryavtsev\, M.V
 . Gorkunov\, and M.A. Osipov\, J. Chem. Phys.\, 146\, 144902 (2017) [4] M.
 V. Gorkunov and M.A. Osipov\, Soft Matter\, 7\, 4348 (2011) <br> [5] M.A. 
 Osipov and M.V. Gorkunov\, ChemPhys.Chem. 15\, 1496 (2014)<br> [6] M.A. Os
 ipov and M.V. Gorkunov\, Phys. Rev. E \, 92\, 032501 (2015)<br> [7] Osipov
 \, M. A. and Gorkounov\, M. V. in Liquid Crystals with Nano and Microparti
 cles. Lagerwall\, J. P. F. and Scalia\, G. (eds.). Singapore: World Scient
 ific Publishing Company\, 2016.<br> <br>
LOCATION:Seminar Room 1\, Newton Institute
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