Influence of Semiperfluorinated Chains on the Liquid Crystalline Properties of Amphiphilic Polyols:  Novel Materials with Thermotropic Lamellar, Columnar, Bicontinuous Cubic, and Micellar Cubic Mesophases

Cheng, Xiaonong; Das, Malay Kumar; Diele, Siegmar; Tschierske, Carsten

doi:10.1021/la015770i

Cited by 79 publications

(52 citation statements)

References 68 publications

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“…[175,176] A variety of liquid-crystalline phases, that is, micellar cubic, hexagonal columnar, bicontinuous cubic, and smectic phases, are generated by tuning a balance of the volume fraction of the two incompatible parts and the molecular shape. For the series 48-50, the increase in the number of lipophilic chains drastically changes the mesophase patterns.…”

Section: Liquid Crystalsmentioning

confidence: 99%

Functional Liquid‐Crystalline Assemblies: Self‐Organized Soft Materials

2005

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In the 21st century, soft materials will become more important as functional materials because of their dynamic nature. Although soft materials are not as highly durable as hard materials, such as metals, ceramics, and engineering plastics, they can respond well to stimuli and the environment. The introduction of order into soft materials induces new dynamic functions. Liquid crystals are ordered soft materials consisting of self-organized molecules and can potentially be used as new functional materials for electron, ion, or molecular transporting, sensory, catalytic, optical, and bio-active materials. For this functionalization, unconventional materials design is required. Herein, we describe new approaches to the functionalization of liquid crystals and show how the design of liquid crystals formed by supramolecular assembly and nano-segregation leads to the formation of a variety of new self-organized functional materials.

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Section: Liquid Crystalsmentioning

confidence: 99%

Functional Liquid‐Crystalline Assemblies: Self‐Organized Soft Materials

2005

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“…As a result, the introduction of perfluoroalkylated groups into large discotic PAHs paves the way toward the possibility of tuning their liquid crystalline phases into various ones which have been detected, so far, for smaller aromatic molecules bearing fluorinated groups. [41][42][43] …”

Section: Liquid Crystalline Propertiesmentioning

confidence: 99%

Mesomorphic Hexabenzocoronenes Bearing Perfluorinated Chains

et al. 2005

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IntroductionExtended polyaromatic hydrocarbons (PAH) are finding increasing interest among other self-assembled supramolecular systems due to their pronounced tendency for formation of extended π-stacked assemblies. These have many potential properties, such as a high electron density which allows their use in promising applications in molecular electronics. 1 However, the main drawback of these rigid polycondensed molecules resides in the difficulty of their synthesis and their very low solubility which prevents their isolation and manipulation. Recently, Müllen and co-workers 2 succeeded in finding a versatile synthesis of hexa-perihexabenzocoronene (HBC), a polycondensed hexagonal molecule containing 13 benzene rings which shows a very high chemical stability 3 and which self-organizes into columnar stacks, by π-stacking, with an outstanding degree of order in the solid state. 4,5 Additionally, its solubility was improved by the addition of peripheral long aliphatic chains which at the same time bestows the molecule with a ditopic property: These HBC derivatives show a liquid crystalline (LC) state over a wide temperature range depending on the length of the aliphatic chain. 6 Moreover, these HBC derivatives exhibit the highest charge carrier mobility recorded so far for an organic molecule both in the solid and in the liquid crystalline states, 7 paving the way toward their application in the domain of electronic 8 and optoelectronic 9-11 devices.Nevertheless, the lateral interaction between the adjacent HBC stacks caused by the crystalline packing of their aliphatic side chains 12 constitutes a major drawback since it interferes with the formation of very long conducting π-stacks. Additionally, most of the HBCs bearing aliphatic chains are liquid crystalline just above room temperature, which leads to a second disadvantage since it induces a drastic decrease of their charge carrier mobilities, 13 which is reported to be due to "lateral" conduction and as a reason for the perturbation or the deterioration of an ideal liquid crystalline mesophase that dominates the conduction process. 14 * To whom correspondence should be addressed. Tel. (Office): +41 (0) Synthesis and characterization of new hexabenzocoronene (HBC) derivatives bearing perfluoroalkylated chains are described. These disc-shaped polycondensed aromatic hydrocarbons are known to self-assemble by π-stacking into columnar architectures. The peripheral decoration with perfluorinated chains, well-known for their low van der Waals forces, leads as expected to reduced intercolumnar interactions. Powder X-ray diffraction and differential scanning calorimetry of these perfluoroalkylated HBCs proved liquid crystalline (LC) properties whose transition temperatures, mesophase stability, and nature depend on the detailed structure of these side chains, i.e., the ratio between aliphatic and perfluorinated parts. On the other hand, the insertion of a phenyl spacer between the aromatic core and the lateral chains increases the LC transition temperature and, sur...

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“…To this end, Tschierske et al, have shown that in conventional pendant chain liquid crystalline polymers, the volume fraction of the pendant chains plays an important role in defining the final curvature of the domain interfaces. 25,26 Furthermore, we have recently demonstrated that in columnar liquid crystalline phases based on dendronized polymer/alkyl tail ionic complexes, an ''inverted'' configuration (that is pendant chains in the columns), is possible also at large volume fractions of pendant chains.…”

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confidence: 99%

Frustrated self-assembly of dendron and dendrimer-based supramolecular liquid crystals

Mezzenga¹,

Ruokolainen²,

Canilho³

et al. 2009

Soft Matter

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A new ''inverted'' topological configuration is demonstrated both experimentally and theoretically for self-assembled dendron and dendrimer-based supramolecular liquid crystals in which the dendrons/ dendrimers occupy the continuous domain and the ionically attached pendant chains are confined in discrete domains. All previous studies on dendrimer and dendron-based liquid crystals have reported ''normal'' liquid crystalline configurations in which the dendritic templates occupy discrete domains (in spherical or columnar phases) or continuous struts (in bicontinuous cubic phases), while the pendant chains occupy the continuous space-filling domain. These surprising results mandate a re-examination of the packing mechanisms for this important class of materials and open new routes to unique nanostructures of possible use in existing and emerging technologies.Supramolecular self-assembly of polymers offers nearly limitless possibilities when the architecture of the macromolecular template, the nature of the supramolecular interactions and the diversity of the ligands (tectons) attached to the polymer backbone are fully exploited.

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Influence of Semiperfluorinated Chains on the Liquid Crystalline Properties of Amphiphilic Polyols: Novel Materials with Thermotropic Lamellar, Columnar, Bicontinuous Cubic, and Micellar Cubic Mesophases

Cited by 79 publications

References 68 publications

Functional Liquid‐Crystalline Assemblies: Self‐Organized Soft Materials

Functional Liquid‐Crystalline Assemblies: Self‐Organized Soft Materials

Mesomorphic Hexabenzocoronenes Bearing Perfluorinated Chains

Frustrated self-assembly of dendron and dendrimer-based supramolecular liquid crystals

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