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CATEGORIES:Isaac Newton Institute Seminar Series
SUMMARY:Orientational ordering and self-organisation of na
noparticles in liquid crystal and polymer nanocomp
osites - Mikhail Osipov (University of Strathclyde
)
DTSTART;TZID=Europe/London:20190514T164000
DTEND;TZID=Europe/London:20190514T170000
UID:TALK124420AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/124420
DESCRIPTION:Nematic liquid crystals (LCs) and block copolymers
doped with nanoparticles possess a number of inte
resting properties. In particular\, anisotropic na
noparticles are orientationally ordered in the bou
ndary region between the blocks [1-3] and a small
concentration of nanoparticles can shift the trans
ition temperatures between different phases\, orie
ntational ordering of nanoparticles is responsible
for the enhanced dielectric anisotropy of the com
posite lamellae and hexagonal phases which opens a
possibility to align block copolymers by external
fields. This may enable one to solve various appl
ication problems. We first summarise the results o
f a molecular theory of nematic LCs doped with ani
sotropic nanoparticles and describe the effect of
nanoparticles on the N-I phase transition\, the ne
matic order parameter and consider the formation o
f chains of polar nanoparticle [4-7]. We then pres
ent the results of a molecular theory of the induc
ed orientational order of anisotropic nanoparticle
s in the lamellae and in the hexagonal phase of a
diblock copolymer taking into anisotropic interact
ion between nanoparticles and the polymer chains.
Numerical concentration and orientational order pa
rameter profiles are presented for different value
s of the model parameters including the strength o
f the anisotropic interaction. We also present the
results of the general mean-field theory which en
ables one to describe both the effect of segregati
on of monomers between different blocks on the ori
entational order of nanoparticles and the effect o
f nanoparticles on the stability of different phas
es..
Finally we present the results of the com
puter simulations of the lamellae and hexagonal co
polymer nanocomposites doped with nanoparticles of
different length and affinity\, and the simulated
concentration and order parameter profiles are co
mpared with theoretical results [1\,3]. We also di
scuss the corresponding phase diagrams which illus
trate how the nanoparticles may effect the phase b
ehaviour of block copolymers.
References
[
1] Osipov\, M. A.\, Gorkunov\, M. V.\, Berezkin\,
A. V.\, Kudryavtsev\, Y. V.\, Phys. Rev. E\, 97\,
042706 (2018)
[2] M.A. Osipov and M.V. Gorkun
ov\, Eur.Phys.J.\, 39\, 126 (2016)
[3] A.V. B
erezkin\, 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)
[5] M.A. Osipov and M.V. Gork
unov\, ChemPhys.Chem. 15\, 1496 (2014)
[6] M.A
. Osipov and M.V. Gorkunov\, Phys. Rev. E \, 92\,
032501 (2015)
[7] Osipov\, M. A. and Gorkounov
\, M. V. in Liquid Crystals with Nano and Micropar
ticles. Lagerwall\, J. P. F. and Scalia\, G. (eds.
). Singapore: World Scientific Publishing Company\
, 2016.
LOCATION:Seminar Room 1\, Newton Institute
CONTACT:INI IT
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