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Special Issue "Advances in Colorants"

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A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (31 January 2013)

Special Issue Editor

Guest Editor
Prof. Dr. Harold Freeman

College of Textiles, North Carolina State University, NC 27695, USA
Interests: color and dye chemistry and sciences; energy; environment and sustainability

Special Issue Information

Dear Colleagues,

Until the dawning of the 21st century, advances in new colorants centered on their use in the textiles arena. While there is continuing activity in this important sector, it is now evident that organic dyes and pigments enjoy widespread use for a variety of interesting and promising non-textile, high-tech applications. The use of colorants in food, drug, and cosmetic products, in digital printing and photography, and in biological/histological stains is now matched, if not superseded, by their utility in areas such as cancer phototherapy, solar energy capture and storage, optical imaging, and color laser marking for document security. The associated “functional dyes” demonstrate the long-standing viability of the field of color chemistry and point to the need for an organized update on the present topic. It was envisioned that the coverage would involve recent developments in the molecular design, synthesis, characterization (structural and ecological), and application of organic dyes and pigments covering the visible and near-infrared regions. In addition, the resurgence of natural dyes as part of the environmental stewardship message makes this topic worthwhile to cover.While this issue will not be exhaustive in scope, it will be of interest to academic and industrial researchers, making it an indispensable product for both environments.

Prof. Dr. Harold Freeman
Guest Editor

Submission

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed Open Access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs).

Keywords

  • synthesis
  • eco/genotoxicology
  • functional colorants
  • molecular design
  • natural dyes
  • NIR dyes
  • novel structures
  • organic pigments
  • structural analysis
  • textile dyes

Published Papers (8 papers)

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Research

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Open AccessArticle Fractional Factorial Design Study on the Performance of GAC-Enhanced Electrocoagulation Process Involved in Color Removal from Dye Solutions
Materials 2013, 6(7), 2723-2746; doi:10.3390/ma6072723
Received: 21 January 2013 / Revised: 8 April 2013 / Accepted: 10 May 2013 / Published: 10 July 2013
Cited by 24 | PDF Full-text (1206 KB) | HTML Full-text | XML Full-text
Abstract
The aim of this study was to determine the effects of main factors and interactions on the color removal performance from dye solutions using the electrocoagulation process enhanced by adsorption on Granular Activated Carbon (GAC). In this study, a mathematical approach was [...] Read more.
The aim of this study was to determine the effects of main factors and interactions on the color removal performance from dye solutions using the electrocoagulation process enhanced by adsorption on Granular Activated Carbon (GAC). In this study, a mathematical approach was conducted using a two-level fractional factorial design (FFD) for a given dye solution. Three textile dyes: Acid Blue 74, Basic Red 1, and Reactive Black 5 were used. Experimental factors used and their respective levels were: current density (2.73 or 27.32 A/m2), initial pH of aqueous dye solution (3 or 9), electrocoagulation time (20 or 180 min), GAC dose (0.1 or 0.5 g/L), support electrolyte (2 or 50 mM), initial dye concentration (0.05 or 0.25 g/L) and current type (Direct Current—DC or Alternative Pulsed Current—APC). GAC-enhanced electrocoagulation performance was analyzed statistically in terms of removal efficiency, electrical energy, and electrode material consumptions, using modeling polynomial equations. The statistical significance of GAC dose level on the performance of GAC enhanced electrocoagulation and the experimental conditions that favor the process operation of electrocoagulation in APC regime were determined. The local optimal experimental conditions were established using a multi-objective desirability function method. Full article
(This article belongs to the Special Issue Advances in Colorants)
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Open AccessArticle Density Functional Theory (DFT) Study of Coumarin-based Dyes Adsorbed on TiO2 Nanoclusters—Applications to Dye-Sensitized Solar Cells
Materials 2013, 6(6), 2372-2392; doi:10.3390/ma6062372
Received: 1 February 2013 / Revised: 17 April 2013 / Accepted: 18 April 2013 / Published: 10 June 2013
Cited by 16 | PDF Full-text (2041 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Coumarin-based dyes have been successfully used in dye-sensitized solar cells, leading to photovoltaic conversion efficiencies of up to about 8%. Given the need to better understand the behavior of the dye adsorbed on the TiO2 nanoparticle, we report results of density [...] Read more.
Coumarin-based dyes have been successfully used in dye-sensitized solar cells, leading to photovoltaic conversion efficiencies of up to about 8%. Given the need to better understand the behavior of the dye adsorbed on the TiO2 nanoparticle, we report results of density functional theory (DFT) and time-dependent DFT (TD-DFT) studies of several coumarin-based dyes, as well as complex systems consisting of the dye bound to a TiO2 cluster. We provide the electronic structure and simulated UV-Vis spectra of the dyes alone and adsorbed to the cluster and discuss the matching with the solar spectrum. We display the energy level diagrams and the electron density of the key molecular orbitals and analyze the electron transfer from the dye to the oxide. Finally, we compare our theoretical results with the experimental data available and discuss the key issues that influence the device performance. Full article
(This article belongs to the Special Issue Advances in Colorants)
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Open AccessArticle Characterization of Natural Dyes and Traditional Korean Silk Fabric by Surface Analytical Techniques
Materials 2013, 6(5), 2007-2025; doi:10.3390/ma6052007
Received: 4 February 2013 / Revised: 2 May 2013 / Accepted: 3 May 2013 / Published: 15 May 2013
Cited by 4 | PDF Full-text (1074 KB) | HTML Full-text | XML Full-text
Abstract
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS) are well established surface techniques that provide both elemental and organic information from several monolayers of a sample surface, while also allowing depth profiling or image mapping to be carried out. [...] Read more.
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS) are well established surface techniques that provide both elemental and organic information from several monolayers of a sample surface, while also allowing depth profiling or image mapping to be carried out. The static TOF-SIMS with improved performances has expanded the application of TOF-SIMS to the study of a variety of organic, polymeric and biological materials. In this work, TOF-SIMS, XPS and Fourier Transform Infrared (FTIR) measurements were used to characterize commercial natural dyes and traditional silk fabric dyed with plant extracts dyes avoiding the time-consuming and destructive extraction procedures necessary for the spectrophotometric and chromatographic methods previously used. Silk textiles dyed with plant extracts were then analyzed for chemical and functional group identification of their dye components and mordants. TOF-SIMS spectra for the dyed silk fabric showed element ions from metallic mordants, specific fragment ions and molecular ions from plant-extracted dyes. The results of TOF-SIMS, XPS and FTIR are very useful as a reference database for comparison with data about traditional Korean silk fabric and to provide an understanding of traditional dyeing materials. Therefore, this study shows that surface techniques are useful for micro-destructive analysis of plant-extracted dyes and Korean dyed silk fabric. Full article
(This article belongs to the Special Issue Advances in Colorants)
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Open AccessCommunication The Development of Novel Near-Infrared (NIR) Tetraarylazadipyrromethene Fluorescent Dyes
Materials 2013, 6(5), 1779-1788; doi:10.3390/ma6051779
Received: 31 January 2013 / Revised: 19 April 2013 / Accepted: 22 April 2013 / Published: 6 May 2013
Cited by 4 | PDF Full-text (443 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Novel structures of an near-infrared (NIR) tetraarylazadipyrromethene (aza-BODIPY) series have been prepared. We designed the core structure containing two amido groups at the para-position of the aromatic rings. The amido group was incorporated to secure insensitivity to pH and to ensure a [...] Read more.
Novel structures of an near-infrared (NIR) tetraarylazadipyrromethene (aza-BODIPY) series have been prepared. We designed the core structure containing two amido groups at the para-position of the aromatic rings. The amido group was incorporated to secure insensitivity to pH and to ensure a bathochromic shift to the NIR region. Forty members of aza-BODIPY compounds were synthesized by substitution of the acetyl group with commercial amines on the alpha bromide. The physicochemical properties and photostability were investigated and the fluorescence emission maxima (745~755 nm) were found to be in the near infrared (NIR) range of fluorescence. Full article
(This article belongs to the Special Issue Advances in Colorants)

Review

Jump to: Research

Open AccessReview Dye Sensitizers for Photodynamic Therapy
Materials 2013, 6(3), 817-840; doi:10.3390/ma6030817
Received: 31 January 2013 / Revised: 20 February 2013 / Accepted: 22 February 2013 / Published: 6 March 2013
Cited by 89 | PDF Full-text (304 KB) | HTML Full-text | XML Full-text
Abstract
Photofrin® was first approved in the 1990s as a sensitizer for use in treating cancer via photodynamic therapy (PDT). Since then a wide variety of dye sensitizers have been developed and a few have been approved for PDT treatment of skin [...] Read more.
Photofrin® was first approved in the 1990s as a sensitizer for use in treating cancer via photodynamic therapy (PDT). Since then a wide variety of dye sensitizers have been developed and a few have been approved for PDT treatment of skin and organ cancers and skin diseases such as acne vulgaris. Porphyrinoid derivatives and precursors have been the most successful in producing requisite singlet oxygen, with Photofrin® still remaining the most efficient sensitizer (quantum yield = 0.89) and having broad food and drug administration (FDA) approval for treatment of multiple cancer types. Other porphyrinoid compounds that have received approval from US FDA and regulatory authorities in other countries include benzoporphyrin derivative monoacid ring A (BPD-MA), meta-tetra(hydroxyphenyl)chlorin (m-THPC), N-aspartyl chlorin e6 (NPe6), and precursors to endogenous protoporphyrin IX (PpIX): 1,5-aminolevulinic acid (ALA), methyl aminolevulinate (MAL), hexaminolevulinate (HAL). Although no non-porphyrin sensitizer has been approved for PDT applications, a small number of anthraquinone, phenothiazine, xanthene, cyanine, and curcuminoid sensitizers are under consideration and some are being evaluated in clinical trials. This review focuses on the nature of PDT, dye sensitizers that have been approved for use in PDT, and compounds that have entered or completed clinical trials as PDT sensitizers. Full article
(This article belongs to the Special Issue Advances in Colorants)
Open AccessReview Solubilization of Hydrophobic Dyes in Surfactant Solutions
Materials 2013, 6(2), 580-608; doi:10.3390/ma6020580
Received: 14 January 2013 / Revised: 10 February 2013 / Accepted: 15 February 2013 / Published: 21 February 2013
Cited by 33 | PDF Full-text (779 KB) | HTML Full-text | XML Full-text
Abstract
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, [...] Read more.
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. Full article
(This article belongs to the Special Issue Advances in Colorants)
Open AccessReview A Review of Aspects of Oxidative Hair Dye Chemistry with Special Reference to N-Nitrosamine Formation
Materials 2013, 6(2), 517-534; doi:10.3390/ma6020517
Received: 5 January 2013 / Revised: 23 January 2013 / Accepted: 28 January 2013 / Published: 13 February 2013
Cited by 6 | PDF Full-text (212 KB) | HTML Full-text | XML Full-text
Abstract
This review discusses a new aspect to the safety profile of oxidative hair dyes using data already in the public domain. These dyes contain secondary amines that are capable of forming potentially carcinogenic nitrosamine derivatives when exposed to atmospheric pollution. Numerous scientific [...] Read more.
This review discusses a new aspect to the safety profile of oxidative hair dyes using data already in the public domain. These dyes contain secondary amines that are capable of forming potentially carcinogenic nitrosamine derivatives when exposed to atmospheric pollution. Numerous scientific articles confirm the existence of secondary amines in hair dyes (and their intermediates), the possibility of nitrosation by atmospheric NOx of secondary amines to give the N-nitrosamines, and the significant safety risks on N-nitrosamines. It is believed that such nitrosamine derivatives should be investigated more fully in the interests of consumer safety. Full article
(This article belongs to the Special Issue Advances in Colorants)
Open AccessReview Organic and Inorganic Dyes in Polyelectrolyte Multilayer Films
Materials 2012, 5(12), 2681-2704; doi:10.3390/ma5122681
Received: 13 November 2012 / Revised: 3 December 2012 / Accepted: 4 December 2012 / Published: 10 December 2012
Cited by 10 | PDF Full-text (935 KB) | HTML Full-text | XML Full-text
Abstract
Polyelectrolyte multilayer films are a versatile functionalization method of surfaces and rely on the alternated adsorption of oppositely charged species. Among such species, charged dyes can also be alternated with oppositely charged polymers, which is challenging from a fundamental point of view, [...] Read more.
Polyelectrolyte multilayer films are a versatile functionalization method of surfaces and rely on the alternated adsorption of oppositely charged species. Among such species, charged dyes can also be alternated with oppositely charged polymers, which is challenging from a fundamental point of view, because polyelectrolytes require a minimal number of charges, whereas even monovalent dyes can be incorporated during the alternated adsorption process. We will not only focus on organic dyes but also on their inorganic counterparts and on metal complexes. Such films offer plenty of possible applications in dye sensitized solar cells. In addition, dyes are massively used in the textile industry and in histology to stain textile fibers or tissues. However, the excess of non bound dyes poses serious environmental problems. It is hence of the highest interest to design materials able to adsorb such dyes in an almost irreversible manner. Polyelectrolyte multilayer films, owing to their ion exchange behavior can be useful for such a task allowing for impressive overconcentration of dyes with respect to the dye in solution. The actual state of knowledge of the interactions between charged dyes and adsorbed polyelectrolytes is the focus of this review article. Full article
(This article belongs to the Special Issue Advances in Colorants)

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