Li+ and K+ ionic conductivity in ionic nematic liquid crystals based on 18-diaza-crown ether substituted with six decylalkoxy-p-cyanobiphenyl chains

Conejo-Rodríguez, Verónica; Cuerva, Cristián; Schmidt, Rainer; Bardajı́, Manuel; Espinet, Pablo

doi:10.1039/c8tc04898c

Cited by 8 publications

(10 citation statements)

References 61 publications

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“…The calculated mobility for KX-2c with different anions was in the order of 10 −12 -10 −10 cm 2 V −1 s −1 , which is four orders of magnitude lower than the hole mobility of the neat 18-crown-6 2c. This again correlates well with the results by Bardaj, Espinet, and coworkers, which observed 20 times higher conductivity, when the crown ether metal complex was doped with the neat "empty" crown [35].…”

Section: Discussionsupporting

confidence: 91%

“…Thus, the existence of channels for fast cation transport could be excluded. It should be noted that Bardaj, Espinet, and coworkers recently reported similar ionic conductivities for K + complexes of diaza-18-crown-6 ethers carrying six decyloxy-p-cyanobiphenyl chains and showing nematic mesophases [35]. The corresponding Li + complexes showed 10 times higher conductivity, which was rationalized by cations that were jumping from one crown to another close to it [35].…”

Section: Discussionmentioning

confidence: 65%

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Improved Electronic Transport in Ion Complexes of Crown Ether Based Columnar Liquid Crystals

et al. 2019

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The Li+- and K+-complexes of new discotic mesogens, where two n-alkoxy-substituted triphenylene cores are connected by a central crown ether (12-crown-4 and 18-crown-6), provide interesting structural and electronic properties. The inter- and intra-columnar structure was investigated by small and wide angle X-ray scattering. The electronic and ionic transports were studied by temperature dependent photoconductivity and impedance spectroscopy, respectively. Besides a strong increase of the stability and the width of the columnar phases the presence of soft anions (iodide, thiocyanate, tetrafluoroborate) leads to an improved intra-columnar order. The hereby shortened stacking-distance of the triphenylene cores leads to a significant increase of the photoconductivity in the columnar mesophase. Furthermore, the ionic conductivity of the new materials was investigated on macroscopically aligned thin films. The existence of channels for fast cation transport formed by the stacked crown ether moieties in the centre of each column can be excluded. The cations are coordinated strongly and therefore contributing only little to the conductivity. The ionic conductivity is dominated by the anisotropic migration of the non-coordinated anions through the liquid, like side chains favouring the propagation parallel to the columns. Iodide migrates about 20 times faster than thiocyanate and 100 times faster than tetrafluoroborate.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 65%

Improved Electronic Transport in Ion Complexes of Crown Ether Based Columnar Liquid Crystals

et al. 2019

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“…Чем меньше различие между геометрическими размерами катионов и полости макроциклов, тем выше устойчивость образующихся при связывании ионов металлокомплексов. Примером макроциклических лигандов, комплексующих ионы металлов для создания ЖК, могут служить порфириновые производные [137][138][139] и краун-эфиры [140][141][142]. Причем в качестве мезогенов могут быть задействованы как алкилированные производные макроциклов, так и суперамфифильные комплексы макроцикл-ПАВ.…”

Section: гибридные металломезогенные системы на макроциклической матрицеunclassified

Polyfunctional Nanosystems on Amphiphilic and Hybrid Platform: Self-Assembly, Mesogenic Properties and Application

Zhil’tsova¹,

Ibatullina²,

Mirgorodskaya³

et al. 2020

Liq. Cryst. and their Appl.

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Обзор посвящен анализу современных публикаций в области самоорганизации амфифильных соединений, формирования полифункциональных наносистем различной морфологии, их прикладного потенциала в нано-и биотехнологиях. Рассмотрены самоорганизующиеся системы на основе амфифильных соединений, преимущественно катионных ПАВ, а также на гибридной платформе металл/амфифил. Для серии катионных ПАВ проведен анализ влияния структуры головной группы на функциональную активность (солюбилизирующие, каталитические, антимикробные свойства). Продемонстрированы перспективы их использования в качестве мицеллярных наноконтейнеров для гидрофобных спектральных зондов и лекарственных средств, невирусных векторов и антимикробных препаратов. Обсуждены гибридные системы на амфифильной платформе, в том числе металломицеллярные композиции, включающие металлы различной природы, установлена корреляция структура-активность при варьировании структуры ПАВ и природы металла. Отдельный раздел посвящен металломезогенам на амфифильной платформе, разработке наноматериалов различного назначения на их основе, применению в биомедицине, оптике, катализе. Спецификой таких систем является комбинация свойств, типичных для ПАВ (самоорганизация и поверхностная активность), и особенностей, характерных для координационных соединений (окислительно-восстановительные, каталитические, магнитные и оптические свойства). Введение иона металла может способствовать увеличению температурного интервала и концентрационной области существования мезофаз. Дополнительные возможности расширения морфологического поведения и функциональной активности предоставляет использование макроциклической матрицы, позволяющей создавать новые жидкокристаллические материалы.

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“…Verońica et al studied the temperature-dependent K + conductivities at elevated temperature in a LC containing a cyanobiphenyl mesogen and 18diazacrown ether as an ion-conducting component. 22 The system showed a sudden drop in the K + conductivities when the LC entered the isotropic liquid state, which was attributed to the disruption of structural alignment in the mesophase. These examples illustrate that the correlation between structural organization and ion-conducting properties in a LC is highly nontrivial and system-dependent.…”

Section: Introductionmentioning

confidence: 99%

Ion Transport in 2D Nanostructured π-Conjugated Thieno[3,2-b]thiophene-Based Liquid Crystal

Wang

Sun

et al. 2022

ACS Nano

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Leveraging the self-assembling behavior of liquid crystals designed for controlling ion transport is of both fundamental and technological significance. Here, we have designed and prepared a liquid crystal that contains 2,5-bis(thien-2-yl)thieno[3,2-b]thiophene (BTTT) as mesogenic core and conjugated segment and symmetric tetra(ethylene oxide) (EO4) as polar side chains for ion-conducting regions. Driven by the crystallization of the BTTT cores, BTTT/dEO4 exhibits well-ordered smectic phases below 71.5 °C as confirmed by differential scanning calorimetry, polarized optical microscopy, temperature-dependent wide-angle X-ray scattering, and grazing incidence wide-angle X-ray scattering (GIWAXS). We adopted a combination of experimental GIWAXS and molecular dynamics (MD) simulations to better understand the molecular packing of BTTT/dEO4 films, particularly when loaded with the ion-conducting salt lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). Ionic conduction of BTTT/dEO4 is realized by the addition of LiTFSI, with the material able to maintain smectic phases up to r = [Li+]/[EO] = 0.1. The highest ionic conductivity of 8 × 10–3 S/cm was attained at an intermedium salt concentration of r = 0.05. It was also found that ion conduction in BTTT/dEO4 is enhanced by forming a smectic layered structure with irregular interfaces between the BTTT and EO4 layers and by the lateral film expansion upon salt addition. This can be explained by the enhancement of the misalignment and configurational entropy of the side chains, which increase their local mobility and that of the solvated ions. Our molecular design thus illustrates how, beyond the favorable energetic interactions that drive the assembly of ion solvating domains, modulation of entropic effects can also be favorably harnessed to improve ion conduction.

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Li⁺ and K⁺ ionic conductivity in ionic nematic liquid crystals based on 18-diaza-crown ether substituted with six decylalkoxy-p-cyanobiphenyl chains

Abstract: Several ionic liquid crystals with different anions, based on coordination of K+ or Li+ to diaza-crown ether fragments, are spontaneously conductive without externally induced alignment.

Cited by 8 publications

References 61 publications

Improved Electronic Transport in Ion Complexes of Crown Ether Based Columnar Liquid Crystals

Improved Electronic Transport in Ion Complexes of Crown Ether Based Columnar Liquid Crystals

Polyfunctional Nanosystems on Amphiphilic and Hybrid Platform: Self-Assembly, Mesogenic Properties and Application

Ion Transport in 2D Nanostructured π-Conjugated Thieno[3,2-b]thiophene-Based Liquid Crystal

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