Effects of Introduction of Mesogenic Units in Ammonium Amphiphiles on the Aggregation Behavior in Water

Everaars, Marcel D.; Marcelis, Antonius T. M.; Kuijpers, A.J.; Laverdure, E.; Koronova, J.; Koudijs, A.; Sudhölter, Ernst J. R.

doi:10.1021/la00010a020

Cited by 22 publications

(27 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, the new absorption band is narrower and has lower intensity than that of pure monomeric MO, analogous to literature data. 55 Similar results have been obtained in studies on amphiphiles carrying an azobenzene chromophore unit. 55,56 Here, aggregation is reflected by a hypsochromic shift of the absorption maximum of the chromophore.…”

Section: Resultssupporting

confidence: 75%

Aggregation of Azo Dyes with Cationic Amphiphiles at Low Concentrations in Aqueous Solution

1999

View full text Add to dashboard Cite

The aggregation of a series of n-alkyltrimethylammonium bromide (C n TAB, n = 10, 12, 14, 16, and 18) and 4-n-alkyl-1-methylpyridinium iodide amphiphiles (C m pyI, m = 8, 10, 12, and 14) induced by low concentrations of azo dyes in aqueous solution has been investigated by means of ultraviolet (UV) spectroscopy. It was observed that aggregation takes place at surfactant concentrations far below the cmc of C12TAB, C14TAB, C16TAB, and C18TAB with methyl orange (MO), ethyl orange (EO), and para-methyl red (pMR). Aggregation below the cmc of C10TAB was also induced by EO. In the case of MO and pMR, however, higher dye concentrations were necessary to induce aggregation. Interactions at low surfactant concentrations have also been observed in aqueous solutions of C10pyI, C12pyI, and C14pyI with MO. Binding of methyl red (MR), methyl yellow (MY), and azobenzene sulfonate (ABS) with cationic surfactants below their cmc did not occur. Aggregation was reflected by the appearance of a blue-shifted absorption band in the spectra of the dyes. Precipitates formed in aqueous solutions from the cationic surfactants and MO and pMR are C n TA−MO, C n TA−pMR, and C m py−MO salts and consist of an equimolar ratio of surfactant and dye. In similar experiments with EO, MR, MY, or ABS as the solvatochromic dye molecules, no precipitation occurred, although surfactant−EO salts precipitated at high EO concentration. Dye−surfactant salts formed from C n TAB and MO were found to form myelins in phase penetration experiments. Temperatures at which myelins start to form increase upon increasing alkyl chain length of the surfactant as revealed by optical microscopy. The formation of vesicles from C10TA−MO and from C12TA−MO crystals was indicated by electron microscopy. The presence and position of the ionic group in the dye molecule is important in determining the association. The importance of hydrophobic interactions is revealed by the chain length dependence on the aggregation process and the observation that interactions are absent in ethanol. Electrostatic interactions also play an important role, as shown by the effect of NaCl on the binding process.

show abstract

Section: Resultssupporting

confidence: 75%

Aggregation of Azo Dyes with Cationic Amphiphiles at Low Concentrations in Aqueous Solution

1999

View full text Add to dashboard Cite

show abstract

“…The cluster units were prepared from Cs 2 Mo 6 I i 8 I a 6 and AgOCOC n F 2 n +1 , respectively. Kat + was obtained as a bromide salt form, according to reported procedure . In all cases, a stoichiometric amount of Kat‐Br dissolved in dichloromethane was used in the metathesis reaction to exchange the alkali counter‐cations associated with the cluster unit solubilized in acetone (see the Experimental Section for further details).…”

Section: Resultsmentioning

confidence: 99%

Design and Integration in Electro‐Optic Devices of Highly Efficient and Robust Red‐NIR Phosphorescent Nematic Hybrid Liquid Crystals Containing [Mo₆I₈(OCOC_nF_2n+1)₆]²⁻ (n = 1, 2, 3) Nanoclusters

Prévôt

Amela-Cortés

Manna³

et al. 2015

Adv Funct Materials

View full text Add to dashboard Cite

wileyonlinelibrary.comare also very well known as smart materials to respond easily to external stimuli such as a change of temperature, application of a magnetic or electric fi eld. Thus, conferring new functionalities such as luminescence, redox states, and/or magnetism to LC is a challenge of particular interest to design new materials that would improve the efficiency of existing technologies or develop new ones. [ 3 ] In particular, photoluminescent materials play a key role in photonics, optoelectronics or lighting applications. [ 4 ] In this frame, inorganic luminophores appear as the most appropriate materials in terms of stability as compared to organic compounds which suffer from photo bleaching. Thus, luminescent transition metals, [ 3a,c , 5 ] lanthanide(III), [ 3d , 6 ] quantum dots or nanoparticles [ 7 ] have been introduced in LC giving birth to metallomesogens and liquid crystal nanosciences. [ 5,8 ] Recently, we discovered a new class of luminescent hybrid LC material called clustomesogen that contains transition metal clusters. [ 9 ] These inorganic entities were defi ned by Cotton as a fi nite group of metal atoms linked together by metal-metal bonds and are obtained, as ceramic-like powders, by high temperature solid state synthesis. [ 10 ] So far, three strategies were developed to design clustomesogens: i) a covalent approach in which organic LC promoters are covalently linked on an octahedral metallic cluster core, ii) a supramolecular one that combines electrostatic and host guest interactions to associate the LC organic promoters with an alkali Cs 2 Mo 6 Br 14 ternary salt, and, iii) an ionic approach that takes advantage of the cluster units anionic character to associate them with organic cations bearing the mesogenic promoters. Indeed, the octahedral [M 6 X i 8 X a 6 ] n − cluster units (M = Mo, W, or Re; X i = chalcogen/halogen; X a = halogen; i = inner, a = apical, 2 ≤ n ≤ 4) exhibit emission in the red-NIR area upon excitation in the UV-blue with high photoluminescence quantum yields and possess excited state lifetimes in the range of several tenths of microseconds, thanks to the full delocalization of their valence electrons on the all metallic octahedral scaffold. [ 11 ] These last decades, many efforts have been dedicated to their integration in supramolecular architectures, polymeric frameworks or nanomaterials that take advantage of their intrinsic properties. [ 12 ] Very recently, highly luminescent cluster compounds By combining [Mo 6 I 8 (C n F 2 n +1 COO) 6 ] 2− ( n = 1, 2, 3) nanocluster units with liquid crystalline ammonium cations, a new series of hybrid materials is developed that show a nematic liquid crystal phase, the most fl uid of all LC phase, on a large range of temperatures including room temperature. The photophysical studies performed in the LC state show that these selfassembled hybrid materials emit in the red-NIR with absolute quantum yields up to 0.7 and show a very good photostability under continuous irradiation. They are further integrated up t...

show abstract

“…This phenomenon has been used to investigate the type of organization of azobenzene moieties and other chromophores in self assembled systems, monolayers and LB films. [13,[37][38][39][40][41][42][43][44] According to the molecular exciton theory [36] the angle between the transition dipoles and the line connecting them (h) is one of the parameters defining the direction and size of the band shift (see Fig. 5).…”

Section: Uv/vis Spectroscopy On the Polyelectrolyte Complex Monolayersmentioning

confidence: 99%

Adsorption of linear and star-shaped poly(acrylic acid) to model surfaces formed by amphiphiles at the air/water interface

Schnitter

Engelking

Heise

et al. 2000

Macromol. Chem. Phys.

View full text Add to dashboard Cite

Effects of Introduction of Mesogenic Units in Ammonium Amphiphiles on the Aggregation Behavior in Water

Cited by 22 publications

References 1 publication

Aggregation of Azo Dyes with Cationic Amphiphiles at Low Concentrations in Aqueous Solution

Aggregation of Azo Dyes with Cationic Amphiphiles at Low Concentrations in Aqueous Solution

Design and Integration in Electro‐Optic Devices of Highly Efficient and Robust Red‐NIR Phosphorescent Nematic Hybrid Liquid Crystals Containing [Mo₆I₈(OCOC_nF_2n+1)₆]²⁻ (n = 1, 2, 3) Nanoclusters

Adsorption of linear and star-shaped poly(acrylic acid) to model surfaces formed by amphiphiles at the air/water interface

Contact Info

Product

Resources

About

Effects of Introduction of Mesogenic Units in Ammonium Amphiphiles on the Aggregation Behavior in Water

Cited by 22 publications

References 1 publication

Aggregation of Azo Dyes with Cationic Amphiphiles at Low Concentrations in Aqueous Solution

Aggregation of Azo Dyes with Cationic Amphiphiles at Low Concentrations in Aqueous Solution

Design and Integration in Electro‐Optic Devices of Highly Efficient and Robust Red‐NIR Phosphorescent Nematic Hybrid Liquid Crystals Containing [Mo6I8(OCOCnF2n+1)6]2− (n = 1, 2, 3) Nanoclusters

Adsorption of linear and star-shaped poly(acrylic acid) to model surfaces formed by amphiphiles at the air/water interface

Contact Info

Product

Resources

About

Design and Integration in Electro‐Optic Devices of Highly Efficient and Robust Red‐NIR Phosphorescent Nematic Hybrid Liquid Crystals Containing [Mo₆I₈(OCOC_nF_2n+1)₆]²⁻ (n = 1, 2, 3) Nanoclusters