Anisotropic Self‐Assembly of Photoluminescent Oligo(<i>p</i>‐Phenylenevinylene) Derivatives in Liquid Crystals: An Effective Strategy for the Macroscopic Alignment of <i>π</i>‐Gels

Hirai, Yuki; Babu, Sukumaran Santhosh; Praveen, Vakayil K.; Yasuda, Takuma; Ajayaghosh, Ayyappanpillai; Kato, Takashi

doi:10.1002/adma.200901344

Cited by 59 publications

(46 citation statements)

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“…Examples where such control is highly benefi cial or even crucial for device performance are in optoelectronic devices [8][9][10] and in tissue engineering, where a macroscopically organized polymer scaffold is necessary for the growth of highly aligned tissue, such as muscle fi bers and neural tissue. In nonaqueous solvents (bulk thermotropic liquid crystals), the concept of LC templating was demonstrated successfully [ 10,[26][27][28][29][30][31] but in aqueous solutions unidirectional alignment at large length scales is rarely realized, let alone locally controlled. [ 9,11 ] These techniques all have demonstrated their benefi ts, but also strong limitations such as incompatibility with (aqueous) soft matter, low susceptibilities, and/or poor spatial control across multiple length scales.…”

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“…In nonaqueous solvents (bulk thermotropic liquid crystals), the concept of LC templating was demonstrated successfully [ 10,[26][27][28][29][30][31] but in aqueous solutions unidirectional alignment at large length scales is rarely realized, let alone locally controlled. This approach has numerous advantages: (i) it does not depend on specifi c interactions between the assembly and the template and thus it can be applied to a wide range of materials; (ii) any desired (hierarchical) structure can be imprinted on the substrate and reproduced in the assembly; (iii) the desired product can be (chemically) modifi ed after organization (in our case to generate optically active π-conjugated polymers); and (iv) the template can be removed which only leaves the functional material on the substrate.…”

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Patterning of Soft Matter across Multiple Length Scales

Asdonk

Hendrikse

Romera

et al. 2016

Adv Funct Materials

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2609wileyonlinelibrary.com at the moment. [ 2,7,8 ] While the order within an assembly (nanometer scale) is extremely high, when dispersed, most supramolecular materials form macroscopically isotropic assemblies. Moreover, spatial control at device dimensions is challenging. Examples where such control is highly benefi cial or even crucial for device performance are in optoelectronic devices [8][9][10] and in tissue engineering, where a macroscopically organized polymer scaffold is necessary for the growth of highly aligned tissue, such as muscle fi bers and neural tissue. [11][12][13][14] So far, different strategies toward macroscopic alignment of polymeric and supramolecular materials have been developed, including photolithography, [ 15,16 ] soft lithography, [ 3,16 ] electrospinning, [17][18][19] electric [20][21][22][23] and magnetic [ 24,25 ] fi eld alignment, as well as shear fl ow alignment. [ 9,11 ] These techniques all have demonstrated their benefi ts, but also strong limitations such as incompatibility with (aqueous) soft matter, low susceptibilities, and/or poor spatial control across multiple length scales.In this manuscript, we use liquid crystal (LC) templating with patternable substrates to obtain full spatial control in our self-assembled materials. This approach has numerous advantages: (i) it does not depend on specifi c interactions between the assembly and the template and thus it can be applied to a wide range of materials; (ii) any desired (hierarchical) structure can be imprinted on the substrate and reproduced in the assembly; (iii) the desired product can be (chemically) modifi ed after organization (in our case to generate optically active π-conjugated polymers); and (iv) the template can be removed which only leaves the functional material on the substrate. In nonaqueous solvents (bulk thermotropic liquid crystals), the concept of LC templating was demonstrated successfully [ 10,[26][27][28][29][30][31] but in aqueous solutions unidirectional alignment at large length scales is rarely realized, let alone locally controlled. [ 32 ] The limited success in water is related to the amphiphilic lyotropic LCs that are notoriously diffi cult to align on commonly used substrates such as rubbed polyimide. [ 33,34 ] In addition, these lyotropic LCs are incompatible with electric fi elds (because of dielectric and Joule heating as well electrochemical degradation), and they can interfere with the desired self-assembly process of a supramolecular material. [ 35 ] To overcome these disadvantages, we use a template of a lyotropic chromonic LC (LCLC) which is a rigid plank-like molecule Controlling the organization of functional supramolecular materials at both short and long length scales as well as creating hierarchical patterns is essential for many biological and electrooptical applications. It remains however an extremely challenging objective to date, particularly in water-based systems. In this work, it is demonstrated that water-processable self-assembling materials can be organized from mic...

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Patterning of Soft Matter across Multiple Length Scales

Asdonk

Hendrikse

Romera

et al. 2016

Adv Funct Materials

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“…In our previous studies, a cyanobiphenyl LC mixture, MCB , was used for alignment control of photoluminescent and polymerizable fibers . MCB has been prepared as a liquid crystal to combine with 1.…”

Section: Resultsmentioning

confidence: 99%

“…For example, liquid crystals, external stimuli, and ordered surfaces were used to attain macroscopic alignment of self‐assembled fibers. It was also demonstrated that oriented fibrous aggregates showed significant functions such as efficient carrier transport and polarized photoluminescence …”

Section: Introductionmentioning

confidence: 99%

Self‐Assembled Fibers Containing Stable Organic Radical Moieties: Alignment and Magnetic Properties in Liquid Crystals

Eimura

Umeta

Tokoro

et al. 2016

Chemistry A European J

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Macroscopically oriented stable organic radicals have been obtained by using a liquid-crystalline (LC) gel composed of an l-isoleucine-based low molecular weight gelator containing a 2,2,6,6-tetramethylpiperidine 1-oxyl moiety. The LC gel has allowed magnetic measurements of the oriented organic radical. The gelator has formed fibrous aggregates in liquid crystals via intermolecular hydrogen bonds. The fibrous aggregates of the radical gelator are formed and oriented on cooling by applying a magnetic field to the mixture of liquid crystals and the gelator. Superconducting quantum interference device (SQUID) measurements have revealed that both oriented and nonoriented fibrous aggregates exhibited antiferromagnetic interactions, in which super-exchange interaction constant J is estimated as -0.89 cm(-1) .

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“…Hence, FRET studies have been conducted in micelles [12], reverse micelles [13,14], vesicles [15], liposomes [16], ionic liquids [17,18], supramolecular assemblies [19], DNA [20], quantum dots and cyclodextrins [21], etc. Recently, there has been a spurt in energy transfer studies aimed for the development of novel white light emitting organogels like [22][23][24][25][26][27].…”

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confidence: 99%