Novel morphologies for laterally decorated metaparticles: molecular dynamics simulation
We consider a mesoscale model for nano-sized metaparticles (MPs) composed of a central sphere decorated by polymer chains with laterally attached spherocylinder. The latter mimics the mesogenic (e.g., cyanobiphenyl) group. Molecular dynamics simulations of 100 MPs reveal the existence of two novel m...
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Інститут фізики конденсованих систем НАН України
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| Цитувати: | Novel morphologies for laterally decorated metaparticles: molecular dynamics simulation / A.Y. Slyusarchuk, J.M. Ilnytskyi // Condensed Matter Physics. — 2014. — Т. 17, № 4. — С. 44001: 1–6. — Бібліогр.: 21 назв. — англ. |
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irk-123456789-1534612019-06-15T01:27:53Z Novel morphologies for laterally decorated metaparticles: molecular dynamics simulation Slyusarchuk, A.Y. Ilnytskyi, J.M. We consider a mesoscale model for nano-sized metaparticles (MPs) composed of a central sphere decorated by polymer chains with laterally attached spherocylinder. The latter mimics the mesogenic (e.g., cyanobiphenyl) group. Molecular dynamics simulations of 100 MPs reveal the existence of two novel morphologies: uColh (hexagonal columnar arrangement of MPs with strong uniaxial order of LC groups collinear to the columns axis) and wColh (the same arrangement of MPs but with weak or no LC order). Collinearity of the LC director and the columnar axis in uColh morphology indicates its potentially different opto-mechanical response to an external perturbation as compared to the columnar phase for the terminally attached LC groups. Preliminary analysis of the structures of both phases is performed by studying the order parameters and by visualisation of the MPs arrangements. Different mechanisms for the LC groups reorientation are pointed out for the cases of their terminal and lateral attachment. Розглянуто мезоскопiчну модель нанорозмiрних метачастинок (МЧ), якi складається iз центральної сфери, декорованої полiмерними ланцюжками iз бiчним приєднанням сфероцилiндрiв. Останнi описують мезогеннi (напр. цианобiфенiльнi) групи. Виконанi симуляцiї 100 МЧ за допомогою молекулярної динамiки вказують на iснування двох нових морфологiй: uColh (iз гексагональним стовпцевим впакуванням МЧ та сильним одновiсним впорядкуванням рiдкокристалiчних груп колiнеарно до осi стовпцiв) та wColh (iз тим же впорядкування МЧ але слабким або вiдсутнiм рiдкокристалiчним впорядкуванням). Колiнеарнiсть директора та осi симетрiї стовпцевої фази у морфологiї uColh вказує на її потенцiйно iншу оптикомеханiчну реакцiю на зовнiшнє збурення порiвняно iз стовпцевою фазою для моделi iз кiнцевим приєднанням рiдкокристалiчних груп. Попереднiй аналiз структур обох фаз виконано шляхом дослiдження параметрiв порядку та вiзуалiзацiєю розташування МЧ. Вказано на роль рiзних механiзмiв реорiєнтацiї мезогенiв залежно вiд способу їх приєднання. 2014 Article Novel morphologies for laterally decorated metaparticles: molecular dynamics simulation / A.Y. Slyusarchuk, J.M. Ilnytskyi // Condensed Matter Physics. — 2014. — Т. 17, № 4. — С. 44001: 1–6. — Бібліогр.: 21 назв. — англ. 1607-324X DOI:10.5488/CMP.17.44001 arXiv:1501.02572 PACS: 02.70.Ns, 61.30.Vx, 61.30.Cz, 61.30.Gd http://dspace.nbuv.gov.ua/handle/123456789/153461 en Condensed Matter Physics Інститут фізики конденсованих систем НАН України |
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We consider a mesoscale model for nano-sized metaparticles (MPs) composed of a central sphere decorated by polymer chains with laterally attached spherocylinder. The latter mimics the mesogenic (e.g., cyanobiphenyl) group. Molecular dynamics simulations of 100 MPs reveal the existence of two novel morphologies: uColh (hexagonal columnar arrangement of MPs with strong uniaxial order of LC groups collinear to the columns axis) and wColh (the same arrangement of MPs but with weak or no LC order). Collinearity of the LC director and the columnar axis in uColh morphology indicates its potentially different opto-mechanical response to an external perturbation as compared to the columnar phase for the terminally attached LC groups. Preliminary analysis of the structures of both phases is performed by studying the order parameters and by visualisation of the MPs arrangements. Different mechanisms for the LC groups reorientation are pointed out for the cases of their terminal and lateral attachment. |
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Slyusarchuk, A.Y. Ilnytskyi, J.M. |
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Slyusarchuk, A.Y. Ilnytskyi, J.M. Novel morphologies for laterally decorated metaparticles: molecular dynamics simulation Condensed Matter Physics |
| author_facet |
Slyusarchuk, A.Y. Ilnytskyi, J.M. |
| author_sort |
Slyusarchuk, A.Y. |
| title |
Novel morphologies for laterally decorated metaparticles: molecular dynamics simulation |
| title_short |
Novel morphologies for laterally decorated metaparticles: molecular dynamics simulation |
| title_full |
Novel morphologies for laterally decorated metaparticles: molecular dynamics simulation |
| title_fullStr |
Novel morphologies for laterally decorated metaparticles: molecular dynamics simulation |
| title_full_unstemmed |
Novel morphologies for laterally decorated metaparticles: molecular dynamics simulation |
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novel morphologies for laterally decorated metaparticles: molecular dynamics simulation |
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Інститут фізики конденсованих систем НАН України |
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2014 |
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| citation_txt |
Novel morphologies for laterally decorated metaparticles: molecular dynamics simulation / A.Y. Slyusarchuk, J.M. Ilnytskyi // Condensed Matter Physics. — 2014. — Т. 17, № 4. — С. 44001: 1–6. — Бібліогр.: 21 назв. — англ. |
| series |
Condensed Matter Physics |
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AT slyusarchukay novelmorphologiesforlaterallydecoratedmetaparticlesmoleculardynamicssimulation AT ilnytskyijm novelmorphologiesforlaterallydecoratedmetaparticlesmoleculardynamicssimulation |
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2025-07-14T04:37:07Z |
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2025-07-14T04:37:07Z |
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1837595705315688448 |
| fulltext |
Condensed Matter Physics, 2014, Vol. 17, No 4, 44001: 1–6
DOI: 10.5488/CMP.17.44001
http://www.icmp.lviv.ua/journal
Rapid Communication
Novel morphologies for laterally decorated
metaparticles: Molecular dynamics simulation
A.Y. Slyusarchuk1, J.M. Ilnytskyi2
1 National University “Lviv Polytechnic”, 12 Bandera St., 79013 Lviv, Ukraine
2 Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine,
1 Svientsitskii St., 79011 Lviv, Ukraine
Received October 10, 2014, in final form December 4, 2014
We consider a mesoscale model for nano-sized metaparticles (MPs) composed of a central sphere decorated
by polymer chains with laterally attached spherocylinder. The latter mimics the mesogenic (e.g., cyanobiphenyl)
group. Molecular dynamics simulations of 100 MPs reveal the existence of two novel morphologies: uColh(hexagonal columnar arrangement of MPs with strong uniaxial order of mesogens collinear to the columns
axis) andwColh [the same arrangement of MPs but with weak or no liquid crystalline (LC) order]. Collinearity ofthe LC director and the columnar axis in uColh morphology indicates its potentially different opto-mechanicalresponse to an external perturbation as compared to the columnar phase for the terminally attachedmesogens.
Preliminary analysis of the structures of both phases is performed by studying the order parameters and by
visualisation of the MPs arrangements. Different mechanisms for the mesogens reorientation are pointed out
for the cases of their terminal and lateral attachment.
Key words: nanoparticles, liquid crystals, self-assembly, molecular dynamics
PACS: 02.70.Ns, 61.30.Vx, 61.30.Cz, 61.30.Gd
1. Motivation
Colloid particles, polymers and LC molecules represent main building blocks of soft matter physics
[1]. When two or more of such blocks are combined into a MP, the latter forms a meta-material that ex-
hibits a range of newmorphologies and new effects that are not observed for any of its pure constituents.
Examples to mention are: LC elastomers, LC dendrimers, decorated nanoparticles and others [2–7], all
of these having already found a number of applications in thermo- and photo-controlled elasticity, plas-
monic resonance, photonics and medicine. Most applications rely on the symmetry of the equilibrium
morphology, in which each constituent is “responsible” for particular property of a meta-material. For
instance, its elasticity is usually controlled by a polymer subsystem, optical properties are governed by
both the behaviour of mesogens and the arrangement of gold nanoparticles (if any). Therefore, the type
of mutual arrangement of the constituent parts is crucial regarding the new potential applications of each
particular meta-material.
Let us concentrate on the MPs built out of a spherical core decorated by polymer chains (spacers)
each ending by a mesogen. The core mimics either a solid nanoparticle (e.g., gold nanoparticle [6, 7]) or
averaged in time shape of a dendritic scaffold [4, 5]. It was found experimentally that the most important
aspects of decoration are as follows: the surface density of mesogens on the outer shell of MP, the length
of a spacer, and the exact way mesogens are attached chemically to the spacer [4–11]. In particular,
both terminal and lateral attachment can be realised chemically [4, 5, 8–11] [depicted schematically in
figure 1 (a) and (b)] and the difference between the morphologies observed in these two cases are in the
focus of this study.
© A.Y. Slyusarchuk, J.M. Ilnytskyi, 2014 44001-1
http://dx.doi.org/10.5488/CMP.17.44001
http://www.icmp.lviv.ua/journal
A.Y. Slyusarchuk, J.M. Ilnytskyi
The case of a terminal attachment of mesogens [figure 1 (a)] has been studied more widely out of
the two [4–7]. In particular, at low grafting density of chains such MPs adopt a rod-like conformation
(a) (b) (c) (d)
Figure 1. (Color online) Schematic representation of a MPmade
of a spherical core (shown in pink) decorated via spacers
(shown in gray) each ending by a mesogen (shown in blue).
(a) MP with terminal attachment of mesogens, (b) the same
with lateral attachment, (c) and (d): reorientation options for
attached mesogens for both models (see text for more details).
and self-assembly into lamellar smec-
tic A morphology [see, figure 2 (a)].
With an increase of a grafting den-
sity, the disc-like conformation for MPs
is favoured over the rod-like one, and
the MPs self-assemble into columns
which arrange themselves hexagonally
[see, figure 2 (b)]. Both structures pos-
sess uniaxial symmetry denoted via the
symmetry axis ā. For the morphology
(a) it is defined as a normal vector to
the layers (and it also coincides with
the preferential direction forMPs rods),
whereas for its (b) counterpart ā is de-
fined along the columns of MPs. Despite
this common feature, the different type of MPs arrangement in thesemorphologies will affect their elastic
properties and their behaviour in plasmonic resonance applications (if the cores represent gold nanopar-
ticles). Their behaviourwill differ evenmore in the applications related to the optical activity and orienta-
tional order of mesogens. Indeed, morphology (a) is characterised by an uniaxial preferential orientation
of mesogens defined via nematic director n̄, whereas for the case of morphology (b) the global direc-
tor does not exist. The distribution of mesogens orientations in this case is flat radial centered around
the axes of each column [as indicated in figure 2 (b)]. One can clearly see some analogy with the case
of LC elastomers, where the role of a symmetry axis ā can be attributed to the preferential orienta-
tion of the polymer backbones [2, 3]. It is well known that their opto-mechanical applications depend
heavily on the mutual arrangement of ā and n̄ axes, the main- and side-chain architectures being an
example [2, 3, 12–16].
(a)
n
_
a
_
(b) a
_
(c) a
_
n
_
Figure 2. (Color online) (a) and (b): schematic representation of
lamellar smectic and hexagonal columnar morphology, respec-
tively, observed for the MP decorated by polymer chains with
terminally attached mesogens. (c): uniaxial hexagonal colum-
narmorphology that is expected to exist for the case of laterally
attached mesogens.
Therefore, a question ariseswhether
some other morphologies can be ob-
tained for the MPs with lateral attach-
ment of mesogens [figure 1 (b)] which
are characterised by different mutual
arrangement of the ā and n̄ axes, lead-
ing potentially to new optical and opto-
mechanical behaviour. Based on this
MP geometry, one would expect the for-
mation of hexagonal columnar mor-
phology depicted in figure 2 (c). It
should be quite similar to its counter-
part (b) (shown in the same figure)
in terms of its mechanical properties
and the arrangement of cores, but, cru-
cially, is characterised by uniaxial ori-
entational order with the nematic director shown as n̄ therein. Moreover, are there any other morpholo-
gies possible?We try to provide the answer in the following section bymeans of coarse-grainedmolecular
dynamics simulations.
2. Results and discussion
The model for a MP with laterally attached mesogens is based on its counterpart with terminal at-
tachment described in detail in references [17, 18]. The central sphere represents a core (be it a gold
nanoparticle or a dendritic core) decorated by grafting Nch = 32 chains to it. We use the annealing-like
44001-2
Morphologies for decorated metaparticles
grafting, when the first bead of each chain slides freely on the surface of a central sphere. The effective
diameters of soft beads are based on the coarse-graining of the atomistic model for the generation 3 LC
dendrimer performed in reference [19]. These are: 2.14 nm for a central sphere, 0.62 nm for the first bead
and 0.46 nm for the remaining beads of the spacer which connects mesogens to the central sphere.
The spheres interact via soft repulsive potentials of a quadratic form [17, 18]. The mesogens are mod-
elled as soft spherocylinders of the breadth D = 0.374 nm and of the length-to-breadth ratio L/D = 3.
These dimensions are also used for the visualization purpose. The MP is kept together by means of har-
monic spring potentials, with the same parameters used for the model with terminal attachment [17, 18].
As far as eachmonomer is assumed to represent three hydrocarbons [19] and their dimension is less than
the Kuhn segment length, we introduce the pseudo-valent angles which account for the effective spacer
stiffness [17, 18].
Orthogonal lateral attachment of the mesogen to the spacer [figure 1 (b)] is maintained by employing
two potentials. First one is the usual harmonic bond potential between the center or the last monomer of
the spacer and the center of the spherocylinder, the bond length is 0.3 nm. The second potential is also of
a harmonic type with respect to the angle between the latter bond and the long axis of a mesogen [20].
The equlibrium value for this angle is set equal to θ0 = π/2. The force constant for the latter potential
is set equal to its counterpart for the pseudo-valent angle potential mentioned above (the absolute value
can be found in references [17, 18]).
In this study, we consider the MPs with Nch = 32 grafted chains only. The initial configuration is build
out of 100 such MPs arranged randomly in a simulation box. The initial orientation of grafted chains is
radial, with respect to the central sphere. Typical box dimensions are of the order of 15÷20 nm and the
periodic boundary conditions are used in the simulations. First, a short run is performed of 10000molecu-
lar dynamics steps with a small time step of ∆t = 2 fs to eliminate initial interparticle overlaps. Following
the scheme employed in references [17, 18], we performed field-assisted self-assembly simulations first.
These are done at a fixed temperature T = 520 K by imposing an external orienting field. The latter is
introduced via additional energy termU rot =−∑N
i=1 F cos2ϑi , which contains a contribution from each
i th mesogen. Here, ϑi is the angle between the field direction and the orientation of i th mesogen, F is the
magnitude of the field. Throughout this study we assume that the field is always directed along the Z axis
of the Cartesian frame. Its magnitude F sets a time-scale for the mesogens reorientation and we found
empirically the values in the range of F = (2÷4)·10−20 J to be optimal for our state points. The simulations
are performed in anisotropic isobaric ensemble, where the temperature and each of the three diagonal
components of the stress tensor are maintained constant by means of the thermostat and three separate
barostats [13–16]. This makes possible the auto-adjustment of the simulation box shape which at the end
becomes commensurate with the pitch of the emerging ordered phase. One should remark that the po-
tential interactions used in this model are predominantly soft repulsive (save for the mesogen-mesogen
potential introduced by Lintuvuori and Wilson [21]). Therefore, to maintain the density required for the
ordered phases, the system needs to be stabilized by the pressures of P Ê 50 atm [17, 18].
Thefield-assisted self-assembly simulations are performed for the range of pressures P = 50÷200 atm,
the duration of each run is 106 molecular dynamics steps with a time step of ∆t = 20 fs. For all values of
the pressure within this interval, the system indeed self-assembles into the uniaxial hexagonal columnar
morphology depicted schematically in figure 2 (c) and thereafter referred to in this study as uColh. Depen-dence of this morphology on the pressure is reflected only in the density of stacking of MPs into columns,
as well as in the total density of the system. We will provide simulation snapshots for this morphology
below. The next stage is to test the stability of this structure and the changes it undergoes in a wide range
of temperatures when the aiding field is removed (U rot = 0). To provide a quantitative analysis of these
changes, let us introduce a set of the order parameters.
The level of orientational order of mesogens is described by the nematic order parameter defined as:
SN = 〈P2(cosθi )〉i ,t , (1)
where θi is the angle between the orientation of i th mesogen and nematic director axis n̄, and P2(x) =
1
2 (3x2 −1) is the second Legendre polynomial. The averaging is performed over all mesogens in a system
and over the time trajectory denoted as 〈. . .〉i ,t . The initial director was set along the Z axis in the course
of a field-assisted run. And, similarly to the case of MPs with terminally attached mesogens [17, 18], we
44001-3
A.Y. Slyusarchuk, J.M. Ilnytskyi
found a negligible drift of the director away from this axis for all temperatures where the orientation
order exists whatsoever. Therefore, in this study we assume θi to be the angle between the orientation of
i th mesogen and the Z axis.
X
k
Z
(a) (b)
k
i
Figure 3. (Color online) (a) Flat hexagonal cluster of MPs and
the definition of bond angles ϕk within it. (b) A column of MPsstacked along Z axis.
The amount of the “hexagonality”
in the arrangement of MPs in the
X Y plane can be characterized by the
hexagonal order parameter SH, intro-duced as follows. Let us consider i th
MP and identify its first coordination
circle in the X Y plane. To this end, we
evaluate the bond vectors li k = rk −ri =
{l x
i k , l y
i k , l z
i k } between its center to the
centers of each of its neighbours in-
dexed via k. The bond lengths between i th and kth MPs projected onto the X Y plane are: l x y
i k =[(
l x
i k
)2 + (
l y
i k
)2]1/2. The neighbour k is assumed to belong to the first coordination circle of i th MP if the
following conditions fulfill: Rmin < l x y
i k < Rmax and |l z
i k | < zmax. For our model, we choose the followingset of parameters: Rmin = 4.7 nm, Rmax = 5.3 nm and zmax = 0.2 nm but the choice, obviously, depends on
the geometry of the model MP. After the first coordination circle that contains Nk MPs are identified, thearbitrary axis in the X Y plane is chosen (e.g., the X axis) and the angles ϕk are evaluated for each kth
MPs belonging to this circle [see, figure 3 (a)]. Then, both the local hexagonal order SH,i for i th MP and
its global counterpart SH can be defined via equation (2) as:
SH,i =
∣∣∣∣∣ 1
Nk
Nk∑
k=1
e6 jϕi
∣∣∣∣∣ , SH = 〈SH,i 〉i ,t , SC,i =
Nc,i
Nmax
, SC = 〈SC,i 〉i ,t . (2)
Here, j = p−1. The same equation also contains a definition for the other order parameter, SC, whichaccounts for the “columnarity” of the uColh phase, i.e., the amount of stacking of the MPs discs alongthe Z axis. It can be related to the average columns height which is identified by considering i th MP
and drawing through its center an imaginary cylinder of radius Rc that extends along the Z axis [see,
figure 3 (b)]. Then, one takes into account the number Nc,i of MPs so that their centers are found insidethis cylinder (periodic boundary conditions are not taken into account). Normalisation factor Nmax isintroduced for convenience, to bring the range of SC values to the same interval as the other two orderparameters, SN and SH. We used the following values: Rc = 1 nm and Nmax = 15. These notations explain
the expressions for the columnar order parameter SC in equation (2).
0
0.2
0.4
0.6
300 350 400 450 500 550
uColh wColh C
T, K
SN
SH
SC
Figure 4. Changes undergone by the order parameters SN, SHand SC when uColh morphology, obtained by the field-aidedself-assembly, is equilibrated at various temperatures from
300 K to 560 K. The lines connect data points and serve as
guides only.
Let us concentrate on the behaviour
of the order parameters SN, SH and SCwhen the uniaxial hexagonal columnar
phase uColh, obtained by thefield-aidedself-assembly, is equilibrated at various
temperatures. The plots demonstrating
the changes are provided in figure 4. At
relatively low temperatures, T < 350 K,
the values of all three order parame-
ters are essentially non-zero and one
obtains the uniaxial hexagonal colum-
nar phase uColh first depicted schemat-ically in figure 2 (c). It is characterized
by both uniaxial nematic order along
the Z axis and regular columns of disc-
shapedMPs aligned along the same axis
and arranged hexagonally in the X Y
plane (see snapshots in the left-hand
column of figure 5). With an increase of
the temperature, all order parameters
44001-4
Morphologies for decorated metaparticles
gradually decay to their minimum values. First of all, let us note that SN decays very fast (practicallylinearly), in contrast to the case of terminally attached mesogens [17, 18], where the shape of the curve
for SN had a semi-dome-like shape indicative of a power law form. More importantly, in the case consid-ered there, the decrease of SN and of the asphericity of the molecules was synchronous: both turned tozero at about T = 500 K. For the laterally attached mesogens considered here, we observe an essential
delay in the decrease of two other order parameters, SH and SC, as compared to SN. As one can see infigure 4, there is a narrow temperature range around T = 450 K, where the value of SN dropped to about
0.1 (typical of the isotropic phase), but SH and SC are still almost the same as in the uColh morphologyat T = 300÷ 400 K. One may refer to this morphology as a weak hexagonal columnar (wColh) and theimportant feature of it is that while it lost the orientation order of mesogens, its hexagonal columnar
structure is essentially preserved (see snapshots in the middle column of figure 5). One should note that
the transition from uColh towColh is gradual and the boundary between both shown in figure 4 is ratherfor illustrative purpose. With further heating of the system, the values for the order parameters SH and
SC drop to their minima at approximately T Ê 480 K. The phase observed at the temperatures higher than
that is a cubic phase (C), where the MPs adopt the form close to spherical due to an increased conforma-
tional entropy. Its structure is shown in the right-hand column of figure 5 and is the same as for the case
of terminally attached mesogens [17, 18].
CuColh wColh
X
Y
Z
Figure 5. (Color online) Shapshots showing the structure of
different morphologies. Columns from left to right: uniaxial
hexagonal columnar at T = 300 K (uColh), weak hexagonalcolumnar at T = 450 K (wColh) and cubic at T = 520 K (C) mor-
phologies, all at the pressure of 100 atm. Rows from top to bot-
tom: top view and side view for all respective cases (Cartesian
axes are indicated in the figure).
The faster decay of SN with an in-crease of the temperature and, as a re-
sult, the evidence of a new wColh mor-phology can be explained by the fol-
lowing considerations. Let us go back
to figure 1 (a) and (b) and consider the
difference in the allowed mechanisms
for the mesogens reorientation in both
cases. These are shown schematically
in the same figure, frames (c) and (d)
for the cases of terminal and lateral at-
tachment, respectively. For the case of
a terminal attachment, if we assume
that the grafting point does not drift
much, the only way for a mesogen to
change its orientation is to bend the
spacer [see, figure 1 (c)]. There will
be the energy penalty associated with
this change due to the pseudo-angle
potential term which is introduced to
model the stiffness of the alkyl chain
at a meso-scale level. This mechanism
of bending the chain also exists for the
case of laterally attached mesogens [figure 1 (d), top chain with respect to the central sphere]. However,
there also exists another mechanism of rotating a mesogen around the bond which connects it to the
end monomer of a spacer [figure 1 (d), bottom chains with respect to the central sphere]. This rotation
costs no energy, as far as both bond length between a mesogen and the last monomer and the angle be-
tween the orientation of a mesogen and the same bond stay unchanged. As a result, the rotational motion
of mesogens in the mesogen-rich regions is more decoupled from the elastic energy of the spacers in
the case of laterally attached mesogens compared to the case of their terminal attachment. This is, most
likely, the main reason for a faster decrease of the nematic order with the raise of the temperature in
the former case. We should note that the conformational changes in real systems involve more factors
to be considered, as compared to the current coarse-grained modelling. In particular, both reorientation
mechanisms depicted in figure 1 (d) are likely to be realized via soft interactions such as torsional angles
changes. Therefore, a more detailed analysis is needed to compare the energy penalty for both mecha-
nisms of the mesogens reorientation discussed here.
To conclude, we have shown the possibility of the formation of two novel morphologies, uColh and
44001-5
A.Y. Slyusarchuk, J.M. Ilnytskyi
wColh for the MPs with lateral attachment of mesogens. The former is uniaxial in both the symmetry ofMPs packing and in the arrangement of its mesogens. The latter is characterized by the same symmetry
of MPs packing, while its LC subsystem is in the isotropic phase. Both morphologies differ in their LC
properties from their counterpart for the MPs with terminal attachment of mesogens and are candidates
for specific opto-mechanical applications.
References
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Новi морфологiї метачастинок декорованих шляхом бiчного
приєднання рiдкокристалiчних груп: компютерна симуляцiя
А.Ю. Слюсарчук1, Я.М. Iльницький2
1 Нацiональний унiверситет “Львiвська полiтехнiка”, вул. С. Бандери, 12, 79013 Львiв, Україна
2 Iнститут фiзики конденсованих систем НАН України, вул. I. Свєнцiцького, 1, 79011 Львiв, Україна
Розглянуто мезоскопiчну модель нанорозмiрних метачастинок (МЧ), якi складається iз центральної сфе-
ри, декорованої полiмерними ланцюжками iз бiчним приєднанням сфероцилiндрiв. Останнi описують
мезогеннi (напр. цианобiфенiльнi) групи. Виконанi симуляцiї 100 МЧ за допомогою молекулярної дина-
мiки вказують на iснування двох нових морфологiй: uColh (iз гексагональним стовпцевим впакуванням
МЧ та сильним одновiсним впорядкуванням рiдкокристалiчних груп колiнеарно до осi стовпцiв) та wColh(iз тим же впорядкування МЧ але слабким або вiдсутнiм рiдкокристалiчним впорядкуванням). Колiнеар-
нiсть директора та осi симетрiї стовпцевої фази у морфологiї uColh вказує на її потенцiйно iншу оптико-
механiчну реакцiю на зовнiшнє збурення порiвняно iз стовпцевою фазою для моделi iз кiнцевим при-
єднанням рiдкокристалiчних груп. Попереднiй аналiз структур обох фаз виконано шляхом дослiдження
параметрiв порядку та вiзуалiзацiєю розташування МЧ. Вказано на роль рiзних механiзмiв реорiєнтацiї
мезогенiв залежно вiд способу їх приєднання.
Ключовi слова: наночастинки, рiдкi кристали, самовпорядкування, молекулярна динамiка
44001-6
http://dx.doi.org/10.1007/b97416
http://dx.doi.org/10.1016/S1369-7021(07)70047-0
http://dx.doi.org/10.1039/b413416h
http://dx.doi.org/10.1007/430_2007_077
http://dx.doi.org/10.1002/adfm.201001606
http://dx.doi.org/10.1039/b901793n
http://dx.doi.org/10.1039/b303654e
http://dx.doi.org/10.1021/cm049191l
http://dx.doi.org/10.1021/ma048450p
http://dx.doi.org/10.1080/02678290600973113
http://dx.doi.org/10.1002/anie.200602372
http://dx.doi.org/10.1063/1.2712438
http://dx.doi.org/10.5488/CMP.9.1.87
http://dx.doi.org/10.1063/1.3614499
http://dx.doi.org/10.1039/c2sm26499d
http://dx.doi.org/10.5488/CMP.13.33001
http://dx.doi.org/10.5488/CMP.16.43004
http://dx.doi.org/10.1039/b511082c
http://dx.doi.org/10.1063/1.475017
http://dx.doi.org/10.1063/1.2825292
Motivation
Results and discussion
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