The Giant‐Hexagon Cylinder Network—A Liquid‐Crystalline Organization Formed by a T‐Shaped Quaternary Amphiphile

Prehm, Marko; Liu, Feng; Baumeister, Ute; Zeng, Xiangbing; Ungar, Goran; Tschierske, Carsten

doi:10.1002/ange.200703171

Cited by 21 publications

(12 citation statements)

References 32 publications

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“…Notably, the intracolumnar segregation in the giant 12-octagons, cutting the R F region in half, differs from the usually observed simple core-shell structures, such as in the hexagonal honeycomb of compounds 2 (Fig. 3a), or in similar systems observed previously 34 .…”

Section: Resultscontrasting

confidence: 59%

Arrays of giant octagonal and square cylinders by liquid crystalline self-assembly of X-shaped polyphilic molecules

et al. 2012

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nanopatterning by molecular self-assembly has been a topic of intense research in pursuit of 'bottom-up' methods of generating structures for use in nanotechnology. The systems most widely studied have been two-and three-dimensional morphologies of block copolymers. However, T-and X-shaped polyphilic liquid crystals have recently been shown to have great potential for generating soft honeycomb-like structures, surpassing those of polymers in both complexity and degree of order. The cell cross-section of the liquid crystals honeycombs has so far been limited by small molecular size. Here we overcome this limitation by exploiting the inability of the polyphiles to simultaneously achieve optimal packing and complete nanophase separation. This frustration results in a two-dimensional periodic honeycomb consisting of giant octagonal and square cylinders with circumferences of 12 and 8 molecules, respectively. In addition to forming large cells, the two-molecule-long bendy walls give this structure extra versatility and stability.

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Section: Resultscontrasting

confidence: 59%

Arrays of giant octagonal and square cylinders by liquid crystalline self-assembly of X-shaped polyphilic molecules

et al. 2012

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“…[6] Also, it is well-known that bent-shape molecules form smectic clusters, [18][19][20]27] and more complex-shaped molecules, such as dendrimers, [28] T-shaped, X-shaped, H-shaped, and other anisotropic shaped units, [29][30][31][32][33] can self-assemble into complex supramolecular units. [6] Also, it is well-known that bent-shape molecules form smectic clusters, [18][19][20]27] and more complex-shaped molecules, such as dendrimers, [28] T-shaped, X-shaped, H-shaped, and other anisotropic shaped units, [29][30][31][32][33] can self-assemble into complex supramolecular units.…”

Section: Resultsmentioning

confidence: 99%

“…The ability of branched molecules to form nematic phases, if the branch linkage is sufficiently flexible (thus allowing longrange orientational order), is relatively well-established. [6] Also, it is well-known that bent-shape molecules form smectic clusters, [18][19][20]27] and more complex-shaped molecules, such as dendrimers, [28] T-shaped, X-shaped, H-shaped, and other anisotropic shaped units, [29][30][31][32][33] can self-assemble into complex supramolecular units. Based on these precedents, it is not surprising that our X-ray results confirm the existence of molecular clusters with short-range smectic order.…”

Section: Resultsmentioning

confidence: 99%

Nanostructures of Nematic Materials of Laterally Branched Molecules

et al. 2013

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The synthesis and small-angle X-ray scattering (SAXS) characterization is reported for 20 laterally branched mesogenic molecules, which are derived from the common rod-shaped 2,5-bis([4-(octyloxy)phenyl]carbonyloxy) benzoic acid unit. These compounds have a varying degree of flexibility, in that their lateral branch is formed upon conversion of the acid to either an ester or an amide, and most laterally branched molecules exhibit relatively wide nematic liquid-crystal phases with a direct nematic-to-crystal transition at lower temperatures. SAXS studies reveal the presence of smectic-like nanostructures (clusters) with short-range order in the nematic phase, with characteristic correlation lengths from 3 to over 10 nm. The smectic layers that are contained in these clusters are tilted with respect to the nematic director by angles ranging from 0° (i.e. untilted) to 55°. In some compounds, the intensity of the SAXS peak corresponding to the smectic layer spacing depends strongly on temperature. The main features of the nanostructures can be understood based on the molecular structure; therefore, guiding future synthetic work towards more precisely controlled and technologically useful nanostructures in nematics.

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“…As observed experimentally [10][11][12][13][14][15][16][17] and supported by simulations [18][19][20][21], there is a transition from rhombic or triangular via square, pentagonal to hexagonal cells with growing lateral chain volume or with decreasing rigid core length. Occasionally, complex tiling patterns composed of cells with different shapes were found [22], especially if different lateral chains (e.g., fluorinated and further increased volume, giant honeycombs (Figure 1i-k) [25][26][27] and lamellar phases with coplanar organization of rods (Lam) (Figure 1l-n) were observed [28][29][30][31]. For compounds with branched lateral chains, coaxial rod-bundle phases with cubic network structure (Figure 1o) [32,33] or forming columns on a hexagonal lattice were reported (Figure 1p) [34,35].…”

Section: Methodsmentioning

confidence: 99%

Effects of Lateral and Terminal Chains of X-Shaped Bolapolyphiles with Oligo(phenylene ethynylene) Cores on Self-Assembly Behaviour. Part 1: Transition between Amphiphilic and Polyphilic Self-Assembly in the Bulk

Poppe

Ebert

et al. 2017

Polymers

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Polyphilic self-assembly leads to compartmentalization of space and development of complex structures in soft matter on different length scales, reaching from the morphologies of block copolymers to the liquid crystalline (LC) phases of small molecules. Whereas block copolymers are known to form membranes and interact with phospholipid bilayers, liquid crystals have been less investigated in this respect. Here, series of bolapolyphilic X-shaped molecules were synthesized and investigated with respect to the effect of molecular structural parameters on the formation of LC phases (part 1), and on domain formation in phospholipid bilayer membranes (part 2). The investigated bolapolyphiles are based on a rod-like π-conjugated oligo(phenylene ethynylene) (OPE) core with two glycerol groups being either directly attached or separated by additional ethylene oxide (EO) units to both ends. The X-shape is provided by two lateral alkyl chains attached at opposite sides of the OPE core, being either linear, branched, or semiperfluorinated. In this report, the focus is on the transition from polyphilic (triphilic or tetraphilic) to binary amphiphilic self-assembly. Polyphilic self-assembly, i.e., segregation of all three or four incorporated units into separate nano-compartments, leads to the formation of hexagonal columnar LC phases, representing triangular honeycombs. A continuous transition from the well-defined triangular honeycomb structures to simple hexagonal columnar phases, dominated by the arrangement of polar columns on a hexagonal lattice in a mixed continuum formed by the lipophilic chains and the OPE rods, i.e., to amphiphilic self-assembly, was observed by reducing the length and volume of the lateral alkyl chains. A similar transition was found upon increasing the length of the EO units involved in the polar groups. If the lateral alkyl chains are enlarged or replaced by semiperfluorinated chains, then the segregation of lateral chains and rod-like cores is retained, even for enlarged polar groups, i.e., the transition from polyphilic to amphiphilic self-assembly is suppressed.

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The Giant‐Hexagon Cylinder Network—A Liquid‐Crystalline Organization Formed by a T‐Shaped Quaternary Amphiphile

Cited by 21 publications

References 32 publications

Arrays of giant octagonal and square cylinders by liquid crystalline self-assembly of X-shaped polyphilic molecules

Arrays of giant octagonal and square cylinders by liquid crystalline self-assembly of X-shaped polyphilic molecules

Nanostructures of Nematic Materials of Laterally Branched Molecules

Effects of Lateral and Terminal Chains of X-Shaped Bolapolyphiles with Oligo(phenylene ethynylene) Cores on Self-Assembly Behaviour. Part 1: Transition between Amphiphilic and Polyphilic Self-Assembly in the Bulk

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