Dissipative particle dynamics simulation of quaternary bolaamphiphiles: multi-colour tiling in hexagonal columnar phases

Bates, Martin A.; Walker, Martin

doi:10.1039/b818926a

Cited by 26 publications

(23 citation statements)

References 16 publications

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“…Simulations by coarse-grained and dissipative particle dynamics methods confirmed a large part of the phases shown in figure 5 [63][64][65][66][67] and some of the two-colour tilings [68]. These simulation methods also can be used to predict new tiling patterns [68].…”

Section: X-shaped Polyphiles and Multi-colour Tilingsmentioning

confidence: 93%

“…These simulation methods also can be used to predict new tiling patterns [68]. Nevertheless, molecular design by synthetic chemist combined with sophisticated structure elucidation methods are still required to produce 'intelligent' molecules that would provide new superstructures with even higher complexity.…”

Section: X-shaped Polyphiles and Multi-colour Tilingsmentioning

confidence: 99%

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Complex tiling patterns in liquid crystals

et al. 2011

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In this account recent progress in enhancing the complexity of liquid crystal self-assembly is highlighted. The discussed superstructures are formed mainly by polyphilic T-shaped and X-shaped molecules composed of a rod-like core, tethered with glycerol units at both ends and flexible non-polar chain(s) in lateral position, but also related inverted molecular structures are considered. A series of honeycomb phases composed of polygonal cylinders ranging from triangular to hexagonal, followed by giant cylinder honeycombs is observed for ternary T-shaped polyphiles on increasing the size of the lateral chain(s). Increasing the chain size further leads to new modes of lamellar organization followed by three-dimensional and two-dimensional structures incorporating branched and non-branched axial rod-bundles. Grafting incompatible chains to opposite sides of the rod-like core leads to quaternary X-shaped polyphiles. These form liquid crystalline honeycombs where different cells are filled with different material. Projected on an Euclidian plane, all honeycomb phases can be described either by uniformly coloured Archimedean and Laves tiling patterns (T-shaped polyphiles) or as multi-colour tiling patterns (X-shaped polyphiles). It is shown that geometric frustration, combined with the tendency to segregate incompatible chains into different compartments and the need to find a periodic tiling pattern, leads to a significant increase in the complexity of soft self-assembly. Mixing of different chains greatly enhances the number of possible 'colours' and in this way, periodic structures comprising up to seven distinct compartments can be generated. Relations to biological self-assembly are discussed shortly.

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Section: X-shaped Polyphiles and Multi-colour Tilingsmentioning

confidence: 93%

Section: X-shaped Polyphiles and Multi-colour Tilingsmentioning

confidence: 99%

Complex tiling patterns in liquid crystals

et al. 2011

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“…Essential speed-up for microphase separation can be achieved by using soft potentials [e.g., equations (1)- (3)], since in this case the beads are semi-transparent and may overlap and cross each other during the equilibration (see, e.g., [21,24,[28][29][30][31][32]). However, for the case of the model depicted in figure 1, the spontaneous self-assembly was still found to typically lead to the polydomain (globally isotropic) phase, both in the case of slow cooling down or slow compressing (the results for AE ¿¾ chains are discussed earlier [22]).…”

Section: Bulk Phases Aided and Spontaneous Self-assembly Analysis Omentioning

confidence: 99%

Relation between the grafting density of liquid crystal macromolecule and the symmetry of self-assembled bulk phase: coarse-grained molecular dynamics study

Ilnytskyi¹

2013

Condens. Matter Phys.

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I consider a generic coarse-grained model suitable for the study of bulk self-assembly of liquid crystal (LC) macromolecules. The cases include LC dendrimers, gold nanoparticles modified by polymer chains with terminating LC groups and others. The study is focused on the relation between a number of grafted chains, AE , and the symmetry of the self-assembled bulk phases. Simple space-filling arguments are used first to estimate stability intervals for a rod-like, disc-like and spherulitic conformations in terms of AE . These are followed by coarse-grained molecular dynamics simulations for both spontaneous and aided self-assembly of LC macromolecules into bulk phases. In spontaneous self-assembly runs, essential coexistence of rod-like and disc-like conformations is observed (via analysis of the histograms for the molecular asphericity) in a broad interval of AE , which prevents the formation of defect-free structures. The use of uniaxial and planar aiding fields is found to improve self-assembly into monodomain phases by promoting conformations of respective symmetry. Strong shape-phase relation, observed experimentally, is also indicated by the simulations by the coincidence of the stability intervals for the respective conformations with those for the bulk phases.

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“…Progress has also been made with off-lattice coarse-grained models. For example, quite recently, successful attempts to study the phase behaviour of bolaamphiphiles were accomplished using both molecular dynamics [22,23] and dissipative particle dynamics approaches [24,25]. Both methodologies used spherical sites and represented rigid parts of a mesogen structure by a combination of spherical sites.…”

Section: Introductionmentioning

confidence: 99%

Simulation of bulk phases formed by polyphilic liquid crystal dendrimers

Ilnytskyi¹,

Lintuvuori²,

Wilson³

2010

Condens. Matter Phys.

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A coarse-grained simulation model for a third generation liquid crystalline dendrimer (LCDr) is presented. It allows, for the first time, for a successful molecular simulation study of a relation between the shape of a polyphilic macromolecular mesogen and the symmetry of a macroscopic phase. The model dendrimer consists of a soft central sphere and 32 grafted chains each terminated by a mesogen group. The mesogenic pair interactions are modelled by the recently proposed soft core spherocylinder model of Lintuvuori and Wilson [J. Chem. Phys, 128, 044906, (2008)]. Coarse-grained (CG) molecular dynamics (MD) simulations are performed on a melt of 100 molecules in the anisotropic-isobaric ensemble. The model LCDr shows conformational bistability, with both rod-like and disc-like conformations stable at lower temperatures. Each conformation can be induced by an external aligning field of appropriate symmetry that acts on the mesogens (uniaxial for rod-like and planar for disc-like), leading to formation of a monodomain smectic A (Sm A ) or a columnar (Col) phase, respectively. Both phases are stable for approximately the same temperature range and both exhibit a sharp transition to an isotropic cubic-like phase upon heating. We observe a very strong coupling between the conformation of the LCDr and the symmetry of a bulk phase, as suggested previously by theory. The study reveals rich potential in terms of the application of this form of CG modelling to the study of molecular self-assembly of liquid crystalline macromolecules.

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Dissipative particle dynamics simulation of quaternary bolaamphiphiles: multi-colour tiling in hexagonal columnar phases

Cited by 26 publications

References 16 publications

Complex tiling patterns in liquid crystals

Complex tiling patterns in liquid crystals

Relation between the grafting density of liquid crystal macromolecule and the symmetry of self-assembled bulk phase: coarse-grained molecular dynamics study

Simulation of bulk phases formed by polyphilic liquid crystal dendrimers

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