Indigo and Indigo Colorants

Steingruber, Elmar

doi:10.1002/14356007.a14_149

Cited by 26 publications

(17 citation statements)

References 9 publications

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“…It used to be extracted from plants and used for textile coloration in India, China, and Egypt since 2000 B.C. Synthetic indigo was developed by the German chemist von Baeyer at the end of the nineteenth century and it rapidly took over the market from natural indigo dye [ 31 ]. The original indigo is not soluble in water but it can readily be made water soluble by thiosulfate reduction to the so-called leuco form, “white indigo” (see Figure 2 ).…”

Section: Coloration With Hydrophobic Dyesmentioning

confidence: 99%

Solubilization of Hydrophobic Dyes in Surfactant Solutions

2013

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In this paper, the use of surfactants for solubilization of hydrophobic organic dyes (mainly solvent and disperse dyes) has been reviewed. The effect of parameters such as the chemical structures of the surfactant and the dye, addition of salt and of polyelectrolytes, pH, and temperature on dye solubilization has been discussed. Surfactant self-assemble into micelles in aqueous solution and below the concentration where this occurs—the critical micelle concentration (CMC)—there is no solubilization. Above the CMC, the amount of solubilized dye increases linearly with the increase in surfactant concentration. It is demonstrated that different surfactants work best for different dyes. In general, nonionic surfactants have higher solubilization power than anionic and cationic surfactants. It is likely that the reason for the good performance of nonionic surfactants is that they allow dyes to be accommodated not only in the inner, hydrocarbon part of the micelle but also in the headgroup shell. It is demonstrated that the location of a dye in a surfactant micelle can be assessed from the absorption spectrum of the dye-containing micellar solution.

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Section: Coloration With Hydrophobic Dyesmentioning

confidence: 99%

Solubilization of Hydrophobic Dyes in Surfactant Solutions

2013

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“…1 In the 19 th century, the high commercial value of indigo dyestuffs encouraged early organic chemists to explore synthesis routes to indigos, and indeed the economic race to develop synthetic indigos was a major impetus behind the development of modern synthetic organic chemistry. 2,3 Recently, it was found that indigo, 4 6,6 0 -dibromoindigo, 5 and similar hydrogen-bonded molecules 6,7 show considerable promise for organic electronic applications. In eld-effect transistors, indigos show ambipolar operation with mobility in the range 0.01-1.5 cm 2 V À1 s À1 .…”

Section: Introductionmentioning

confidence: 99%

Air-stable organic semiconductors based on 6,6′-dithienylindigo and polymers thereof

et al. 2014

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“…Originally, it was obtained from the plants Indigofera tinctoria and Isatis tentoria , although with recent advancements in synthesis and fabrication it is almost exclusively produced artificially today. 3,4 Despite the high level of awareness, the formation of highly-crystalline indigo films upon evaporation and the good charge transport properties have only been discovered recently. 5,6 The combination of a reversible oxidation and reduction electrochemistry plus a low bandgap makes such materials behave as ambipolar semiconductors with fairly high mobilities of 0.01 cm 2 /Vs.…”

Section: Introductionmentioning

confidence: 99%

Film growth, adsorption and desorption kinetics of indigo on SiO2

Scherwitzl¹,

Resel²,

Winkler³

2014

The Journal of Chemical Physics

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Organic dyes have recently been discovered as promising semiconducting materials, attributable to the formation of hydrogen bonds. In this work, the adsorption and desorption behavior, as well as thin film growth was studied in detail for indigo molecules on silicon dioxide with different substrate treatments. The material was evaporated onto the substrate by means of physical vapor deposition under ultra-high vacuum conditions and was subsequently studied by Thermal Desorption Spectroscopy (TDS), Auger Electron Spectroscopy, X-Ray Diffraction, and Atomic Force Microscopy. TDS revealed initially adsorbed molecules to be strongly bonded on a sputter cleaned surface. After further deposition a formation of dimers is suggested, which de-stabilizes the bonding mechanism to the substrate and leads to a weakly bonded adsorbate. The dimers are highly mobile on the surface until they get incorporated into energetically favourable three-dimensional islands in a dewetting process. The stronger bonding of molecules within those islands could be shown by a higher desorption temperature. On a carbon contaminated surface no strongly bonded molecules appeared initially, weakly bonded monomers rather rearrange into islands at a surface coverage that is equivalent to one third of a monolayer of flat-lying molecules. The sticking coefficient was found to be unity on both substrates. The desorption energies from carbon covered silicon dioxide calculated to 1.67 ± 0.05 eV for multilayer desorption from the islands and 0.84 ± 0.05 eV for monolayer desorption. Corresponding values for desorption from a sputter cleaned surface are 1.53 ± 0.05 eV for multilayer and 0.83 ± 0.05 eV for monolayer desorption.

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Indigo and Indigo Colorants

Cited by 26 publications

References 9 publications

Solubilization of Hydrophobic Dyes in Surfactant Solutions

Solubilization of Hydrophobic Dyes in Surfactant Solutions

Air-stable organic semiconductors based on 6,6′-dithienylindigo and polymers thereof

Film growth, adsorption and desorption kinetics of indigo on SiO2

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