Discotic liquid crystalline hexabenzocoronenes carrying chiral and racemic branched alkyl chains: supramolecular engineering and improved synthetic methods

Fechtenkötter, Andreas; Tchebotareva, Natalia; Watson, Mark D.; Müllen, Kläus

doi:10.1016/s0040-4020(01)00252-6

Cited by 142 publications

(126 citation statements)

References 65 publications

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“…[5][6][7] Unidirectional π-π interactions, which are characterized by medium-strong binding energies, have also been extensively used to self-assemble small oligomers into discotic liquid crystals with functional properties, such as increased charge mobility. [8][9][10][11] More recently, such interactions have been used to assist self-assembly of π-conjugated rod-coil block copolymers into suitable morphologies for possible use in photovoltaic applications. 12 Hydrogen bonding is characterized by small binding energy compared to other kinds of bonding in supramolecular assemblies, which has allowed the design of comblike polymers with temperature-responsive behavior based on homopolymers with hydrogen-bonding accepting sites and hydrogen-bonding donor surfactants.…”

Section: Introductionmentioning

confidence: 99%

Real Space Imaging and Molecular Packing of Dendronized Polymer−Lipid Supramolecular Complexes

et al. 2007

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The present work describes the molecular structure and the topology in real space of self-assembled comblike liquid crystalline polymers based on supramolecular ionic complexation of dendronized polymers and lipids. The molecular organization was studied as a function of the generation of the dendronized polymers and the length of the lipid tails, both parameters being known to strongly influence the final liquid crystalline (LC) structures stable at thermodynamic equilibrium (Macromolecules 2007(Macromolecules , 40, 2822(Macromolecules -2830. Transmission electron microscopy (TEM) on selectively stained samples allowed imaging of the structures in real space, the identification of individual domains in the various LC phases, and direct comparison of lattice periods with values obtained by small-angle X-ray scattering (SAXS). TEM and SAXS were found in perfect agreement, and surprisingly, the alkyl tails were shown to form the discrete domains in all LC columnar phases. On the basis of these results, various possible molecular packing motifs in the LC phases were considered. First, the combination of density measurements of individual dendronized polymers and lipids with the ratio of lipid-dendronized polymer complexation, measured by elemental analysis, allowed establishing the exact volume fraction of the two supramolecular components and thus, the radii of cylinders and lamellae widths in the various columnar and lamellar LC phases observed. Then, by comparing these topological values with the contour length of the lipids, it was possible to conclude that, in all columnar phases, the lipids adopt a fully stretched configuration with homeotropic arrangement, while in the lamellar phase, lipids tails are essentially interdigitated. The control of lattice periods of LC structures in the range of 2-5 nm and the possibility to confine the lipids in the cylindrical domains make these materials as possible templates for nanoporous materials and ultra densely packed nanochannels.

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Section: Introductionmentioning

confidence: 99%

Real Space Imaging and Molecular Packing of Dendronized Polymer−Lipid Supramolecular Complexes

et al. 2007

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“…Mullen and co-workers 46 prepared HBCs having a variety of chiral or racemic branched side chains, discovering that branching increased HBC solubility and enabled a tuning of the phase transition temperature to provide LC behavior at room temperature. HBC with chiral side chains had a phase transition temperature distinct from their racemic counterparts, and a circular dichroism-couplet at 249 and 218 nm, reflecting chirality of the HBC columns.…”

Section: Nanoscale Assembly T Emrick and E Pentzermentioning

confidence: 99%

Nanoscale assembly into extended and continuous structures and hybrid materials

Emrick

Pentzer

2013

NPG Asia Mater

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Harnessing synthetic power to create novel materials with unique assembly properties is of fundamental interest for pushing the limits of molecular and macromolecular assembly, while further holding the potential for improving electronic and medical device performance. Controlling the assembly of aromatic molecules into nanostructures provides routes towards continuous and extended structures with performance that is improved markedly over that of their individual molecular components, opening possibilities for the formation of composites that have tailored interactions with other materials and thus improved applications. This review covers recent advances in the synthesis of conjugated materials, their controlled assembly into nanoscale architectures and implementation into devices. Specifically, we discuss the solution-based assembly of polythiophene into nanowire fibrils, the formation of columnar stacks of hexabenzocoronene liquid crystals and the preparation of functionalized solution processible graphene for nanocomposite formation.

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“…DLCs are formed by a rigid aromatic core and highly flexible peripheral chains, which provide solubility and drive self-organizing properties of these materials in columns forming different mesophases [13,14].…”

Section: Introductionmentioning

confidence: 99%

“…The relevant properties arise from their self-assembling behavior governed by a combination of the strong p-p overlap between individual molecules [15] and the interaction of peripheral functional groups, which allow the formation of the columnar mesophases [13][14][15][16]. Many theoretical studies have been performed in order to extract the molecular parameters that have direct influence on the electrical transport [5,[17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Doping and photo-induced current in discotic liquid crystals thin films: Long-time and temperature effects

Calò¹,

Stoliar²,

Cavallini³

et al. 2011

Organic Electronics

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. b s t r a c tHere we address the problem of time and temperature instability of the electrical current related to parasitic doping effects in discotic liquid crystals (DLCs). We investigated the electrical transport in thin films of a phthalocyanine-based DLC in-dark and upon laser irradiation during long thermal cycles. Measuring the electrical transport between two electrodes we observed that in-dark the current is mostly due to doping levels while, upon laser irradiation, the photocurrent reflects the diffusion length of the photogenerated charge carriers and it is limited by the coherence length of a column. We prove here that the two contributions are completely independent. Our result experimentally supports the theoretical studies performed at the molecular level on discotic liquid crystals.

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Discotic liquid crystalline hexabenzocoronenes carrying chiral and racemic branched alkyl chains: supramolecular engineering and improved synthetic methods

Cited by 142 publications

References 65 publications

Real Space Imaging and Molecular Packing of Dendronized Polymer−Lipid Supramolecular Complexes

Real Space Imaging and Molecular Packing of Dendronized Polymer−Lipid Supramolecular Complexes

Nanoscale assembly into extended and continuous structures and hybrid materials

Doping and photo-induced current in discotic liquid crystals thin films: Long-time and temperature effects

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