Dyes In Solvents Research Articles

Design of J-aggregates-like oligomers built from squaraine dyes exhibiting transparency in the visible regime and high fluorescence quantum yield in the NIR region.

New materials for transparent luminescent solar concentrators (TLSCs) are of large interest. Therefore, we investigated the optical properties of J-aggregates-like oligomers (hereinafter referred to as J-aggregates) based on covalently bound squaraine dyes in toluene solvent using DFT and TD-DFT methods. In addition, the rate constants needed for the prediction of fluorescence quantum yield (QY) have been calculated using Fermi's Golden rule and vertical harmonic approximation (VH) for ground and excited states. In the context of QY prediction, different broadening of the lineshape has also been employed. We found that J-aggregates based on squaraine dyes exhibit near-infrared (NIR) selective absorption and emission as well as high fluorescence QY. Comparison of the properties obtained for dimers, trimers and tetramers belonging to two classes (SQA and SQB) of J-aggregates allows us to select the tetramer of SQA J-aggregates as suitable for application. The scaling model for N ≥ 4 monomer subunits supports quantitative findings. Therefore, we propose J-aggregates containing N ≥ 4 subunits of SQA with a central squaric acid ring with two oxygen atoms in toluene solvent as a suitable candidate for TLSC application.

Sustainable dispersant-free dyeing of poly(lactic acid) with microbial prodigiosins in decamethylcyclopentasiloxane (D5) medium

Traditional poly(lactic acid) (PLA) dyeing with synthetic disperse dyes in water medium presents a significant environmental risk since it consumes a large amount of chemicals and generates dyeing wastewater. In order to comply with the demands of clean production and sustainable development, a dispersant-free solvent dyeing system was developed by employing decamethylcyclopentasiloxane (D5) as dyeing medium and microbial prodigiosins prepared through surfactant-assisted fermentation as natural disperse dye. The influence of D5 medium on PLA fiber and prodigiosins was investigated. It was discovered that D5 could swell PLA fibers by penetrating the inside of the fibers while having no adverse effects on prodigiosins. The dyeing parameters were subsequently optimized in terms of K/S value and strength loss. The results indicated that PLA fabrics dyed in a modified solvent dyeing system containing 250% (owf) water exhibited the highest K/S value and minimum strength loss when they were dyed at dyeing temperature 105 °C, aqueous pH7.0 and dyeing time 30 min. The colorfastness of solvent dyed fabrics were equivalent to that of aqueously dyed fabrics in terms of rubbing and washing. The solvent dyeing process developed in this study effectively reduces the consumption of dispersant agents, being conducive to facilitate the further development of sustainable PLA industry.

Phenyl versus triazinyl π-Linkers in phenohydrazine, phenoxazine and phenothiazine-based dye-sensitized solar cells: A computational investigation

The present study focuses on designing six new organic dyes derived from phenohydrazine, phenoxazine and phenothiazine, with modifications to the π-linker groups. Different characteristics, including structural, electronic, frontier molecular orbital, chemical reactivity, transition density matrix, molecule electrostatic potential, and driving force parameters, were examined using density functional theory (DFT) at the B3LYP/6–31 G (d,p) level. Additionally, the optical characteristics of the dyes in the CH2Cl2 solvent were evaluated using the time-dependent DFT (TD-DFT) with the TD-BH and H/6–31 G (d,p) method. Geometrical factors, optoelectronic qualities, frontier molecular orbitals, electrostatic surface potential, absorption spectra, and electron-accepting and -donating properties were all included in this thorough investigation. The examined dyes exhibited noteworthy properties, including λmax values ranging from 362.1 to 471.8 nm, band gaps within the range of 1.60–2.34 eV, a high LHE of approximately 0.994 for five dyes, indicating a robust electron-donating capacity, as well as a significant intramolecular charge transfer property. Notably, dyes featuring triazinyl outperformed those with phenyl among the designed compounds.

Chemical recycling of Polylactic acid to methyl lactate catalyzed by choline chloride/ZnCl2 deep eutectic solvents

Methyl lactate (ML) is a green and biodegradable chemical product, which can be used as a solvent for cellulose, paints and dyes. Although several kinds of catalysts have been reported for the methanolysis of Polylactic acid (PLA) into ML, low catalytic activity and high cost and complicated operation are still problems. Renewable, environmentally friendly, and non-toxic choline chloride-based Deep eutectic solvents (DESs) are the newest alternatives to conventional catalysts for the methanolysis of PLA to obtain the valuable product ML. In this study, the methanolysis of PLA into ML using DESs composed of choline chloride (ChCl) and Zinc chloride (ZnCl2) was investigated by experiments and calculations. Experimental results reveal that ChCl-2ZnCl2 can catalyze the methanolysis of PLA to produce ML, more importantly, ML is easily obtained by vacuum distillation, and the catalyst can be reused for 5 times without significant loss of activity. Moreover, the possible reaction mechanism was derived from experimental data and density functional theory (DFT) calculations. And the kinetics of the methanolysis of PLA catalyzed by ChCl-2ZnCl2 was studied and the activation energy was obtained. This work reveals that ChCl/ZnCl2 DESs are conducive to the methanolysis of PLA to ML under moderate conditions, which can also provide strategies for other polymer degradation.

Synthesis of novel carbene dyes and investigation of their dyeing properties and reaction mechanism for various fabrics

Week interactions between traditional dye molecules and synthetic fibers requires addition of numerous chemical additives during the dyeing process, resulting in the generation of a significant amount of printing and dyeing wastewater, thereby causing environmental pollution. Herein, three novel carbene dyes containing diazirine were rationally designed, whose decomposition into carbenes at 145 °C subsequently forms covalent bonds with the C–H bonds present in the fibers. The structure-property relationships of the dyes were analyzed based on the results of density functional theory (DFT) calculations. Additionally, the calculations of Yoshida correlations demonstrated that all three dyes exhibit non-explosive properties, thereby indicating their feasibility for large-scale production. The dyeing process of polyester (polyethylene terephthalate/PET), polypropylene (PP), aramid, spandex, and polyester/spandex (P/S) blended fabrics was performed using a non-aqueous solvent dyeing method without the addition of any additives, and the optimal dyeing and color fixation conditions were determined. The samples dyed with carbene dyes displayed similar K/S values compared to conventionally dyed samples, higher color fixation rates, and improved blended dyeing effects, and the reaction mechanism between the carbene dyes and the fibers was elucidated, which proved the versatility and environmental friendliness of the novel carbene dyes and non-aqueous solvent dyeing method. Furthermore, it is noteworthy that all of these dyed fabrics exhibited exceptional color fastness, highlighting the immense potential of the novel carbene dyes in promoting green production in the textile industry.

Complete recycling of polymers and dyes from polyester/cotton blended textiles via cost-effective and destruction-minimized dissolution, swelling, precipitation, and separation

The lack of economic dye-polymer and fiber-fiber separations for blended textiles prevents large-scale textile recycling. We focus on a clean, cost-effective, and destruction-minimized fiber-to-fiber recycling, suitable for polyester/cotton blended textiles. Here, dyed polyester was dissolved and separated from the blend, followed by controllable polyester precipitation to retain its dyes separately in the solution. The remaining-colored cotton was swollen to remove its dyes after cleavage of dye-cellulose bonds. Colorless polyester and cotton were regenerated into fibers with similar and 60 % higher tenacity than those before the recycling, respectively. Recycled fibers also had desirable dyeability, including dye exhaustion and colorfastness, after being dyed with the dyes extracted from the polyester/cotton blends, via our newly developed solvent dyeing system. More than 99 % of the solvent used in the recycling was recycled. Our recycling had a cost and energy consumption of less than 20 % of the production of virgin materials.

İpeğin Kök Boya İle Edirne Kırmızısı Rengine Boyanması

Silk is a natural filament obtained from the Bombyx mori species of silkworm, with a fiber length of up to 3000 meters. During the Ottoman era in Edirne, sericulture and silk trade were important activities. To this end, silk factories, trade centers, and silk weaving schools were established, creating an important source of income for the people of Edirne. Edirne Red is a natural dye obtained from the Rubia Tinctorum L. plant and is part of the Ottoman Empire's heritage. This dye is resistant to sunlight and washing. It has been used in Turkish carpets, as well as in silk and cotton fabrics. The aim of this study is to bring together the importance of Edirne Red and silk in Edirne's history. For this purpose, 100% silk fabrics were dyed using madder (Rubia Tinctorum L.) grown within the borders of Edirne province. The effects of dye ratios and auxiliary chemicals used on color and colorfastness were examined during the dyeing process. The color values of the fabrics were measured numerically in the CIEL*a*b* color space, and the washing and light fastness values of the dyed fabrics were also measured. Additionally, high-performance liquid chromatography (HPLC) analyses were performed on both the used madder and the dyed fabric. Based on the obtained data, the closest Edirne Red color was achieved by pre-mordanting fabric before dyeing and using ethanol as the dye solvent. Madder dye, successfully applied to silk fabrics under different conditions, has shown good results in terms of color yield and fastness properties.

Effect of Solvent Dyeing Medium on Dye Encapsulation and Non-Aqueous Dyeing of Cotton Fabric with Rhamnolipid (RL) Microbial Biosurfactant-Based Reactive Dye Encapsulated Reverse Micelles

Effect of Solvent Dyeing Medium on Dye Encapsulation and Non-Aqueous Dyeing of Cotton Fabric with Rhamnolipid (RL) Microbial Biosurfactant-Based Reactive Dye Encapsulated Reverse Micelles

Synergism in the solvation of solvatochromic probes in binary mixtures with ionic liquids

The preferential solvation of two perichromic dyes, 4-amino-N-methylphthalimide (4-AMP) and Nile Red (NR) in binary mixtures of an ionic liquid ([bmim][X], where X = BF4, PF6, Tf2N and DCA) with a protic or non-protic solvent, was investigated, in search of examples of a synergetic or “hyperpolar” behavior. Synergism was generally observed in those mixtures where the two pure components had similar polarity values, according to the employed probe. A parallel was drawn between the observed synergism in these IL mixtures and the phenomenon of hydrotropism, also observed with organic solutes in aqueous IL mixtures. More generally, in binary mixtures with organic solvents, ionic liquids can act as solvatotropes, promoting the dye solvation by formation of solute-specific aggregates with all species present in the mixture. By stabilizing the dipolar excited state of 4-AMP or NR through hydrogen-bonds and electrostatic interactions in these aggregates, a “hyperpolar” milieu is generated, which surpasses the polarities of the two pure components. Solvatotropism seems to offer a more realistic picture than the solvent-exchange model, originally developed for simpler systems, to the phenomenon of preferential solvation in binary mixtures with ionic liquids.

How good can a simple artificial neural network predict the medium reorganization energy and the free energy gap from a steady-state fluorescence spectrum?

Medium reorganization energy, Erm, and free energy gap, ΔG, are key characteristics in determining the photoinduced charge transfer rate. They are strongly related to the width and position of the steady-state fluorescence and absorption spectra of organic dyes in solvents. Steady-state spectroscopy is one of the most standard techniques for studying organic dyes. Here, we present a simple machine learning model for cost-effective prediction the medium reorganization energy and the free energy gap from the steady-state fluorescence spectra. Fluorescence spectra with corresponding reference values of physical quantities are calculated using an explicit mathematical expression that addresses electronic-vibrational transitions, intramolecular and solvent reorganizations. An approach to the separate formation of data sets for training and validation is proposed. Gaussian noise is used in training to improve predictions. This study shows that Erm and ΔG can be predicted with the mean absolute error ∼0.024 eV and ∼0.009 eV, respectively. Robustness testing is performed on the experimental spectra of coumarin-153, coumarin-307, and coumarin-522B in a series of solvents.

Emulsion synthesis and transformations of electrokinetic potential of amorphous and crystal TiO2 particles in water, chloroform, n-decane, and n-decane–chloroform mixture

Sols of TiO2 nanoparticles are promising both as the liquid-phase materials in the electrophoretic display (e-book) technology and as the precursors for the formation of various surface films and bulk porous composites with advanced optical, catalytic, photovoltaic and sorption properties. In this work, the synthesis of ultradispersed amorphous TiO2 powders in reverse emulsions stabilized by АОТ is proposed. Sols were obtained from the powders by ultrasonic dispergation in water, n-decane and n-decane–chloroform mixtures. In distinction to commercial nanoparticles, the synthesized amorphous particles in n-decane exhibited a high negative (–55 ± 7 mV) ζ-potential, while in chloroform – a positive (32 ± 3 mV) one. Thermolysis (300–900 °С) of amorphous powders led to the formation of known individual and mixed polymorphous modifications. Surface recharging of amorphous particles was achieved by different methods: by varying the pH of the hydrosol, by dilution of n-decane organosols with chloroform, addition of АОТ, and variation of thermolysis temperature. A wide spectrum of surface charge states and sizes of TiO2 particles in hydro- and organosols was obtained, which makes the produced systems promising for the sorption of both the water-soluble and solvent dyes of different types.

Efficient synthesis and characterization of meso-substituted bis(benzothiazolium) pentamethine cyanine dyes and investigation of the impact of meso-substitution on water solubility and the structural rigidity to improve photophysical properties and fluorescent brightness

To achieve structurally rigid pentamethine cyanine dyes with worthful photophysical properties for biological applications, five series of symmetrical meso-substituted bis(benzothiazolium) pentamethine cyanine dyes were synthesized via an efficient and simple triethylamine-promoted approach involved condensation of various N-substituted benzothiazolium salts with preformed β-substituted vinamidinium salts in high yield and purity without the nontrivial chromatographic separation. The chemical structures of the synthesized dyes were confirmed by HPLC-MS, 1H NMR, 13C NMR, and FTIR techniques. The photophysical properties of the new dyes were investigated in methanol, recognizing that the dyes demonstrate excellent fluorescent brightness. The solutions of the dyes exhibited maximum absorption and fluorescence emission in the range of 600–650 nm with high molar absorption coefficients (around 1-3 × 105 dm3 mol−1 cm−1) and 610–670 nm with remarkable fluorescence quantum yield, respectively. In addition, the photostabilities and photoluminescent stabilities of the synthetic dyes were studied in methanol, revealing their outstanding stability and resistance to photodecomposition. Examining the photochemical behavior (UV light) of the dyes in organic solvents with different polarities verified the main role of various meso substitutions on the rigidity of molecular structures and cis-trans isomerization to improve the photophysical properties. The presence of the pyridinium substituent rings into the polymethine chain makes the dyes rigid and more water-soluble because of their bulky form and positive charge, respectively.

New Solvent Dyes with High Chroma and High Light Stability for Dye Sublimation Thermal Transfer Printer

New Solvent Dyes with High Chroma and High Light Stability for Dye Sublimation Thermal Transfer Printer

Carbon dot-based artificial light-harvesting systems with sequential energy transfer and white light emission for photocatalysis

In this work, we designed and synthesized cationic carbon dots (CDs) with a size distribution of 1.6–3.7 nm, which exhibited dark blue fluorescence in the aqueous solution. Based on its excellent luminescence properties, we used it as an energy donor to construct a sequential artificial light-harvesting system (LHS) by employing the energy-matching dyes eosin Y disodium salt (EY) and sulforhodamine 101 (SR101), which could regulate the white light emission (Commission Internationale de lʼEclairage (CIE) coordinate: (0.30, 0.31)) with the energy transfer efficiency (ΦET) of 53.9% and 20.0%. Moreover, a single-step artificial LHS with white light emission (0.32, 0.28) can be constructed directly using CDs and dye solvent 43 (SR) with ΦET and antenna effect (AE) of 48.8% and 6.5, respectively. More importantly, CDs-based artificial LHSs were firstly used in photocatalytic of α-bromoacetophenone, with a yield of 90%. This work not only provides a new strategy for constructing CDs-based LHSs, but also opens up a new application for further applying the energy harvested in CDs-based LHSs to the field of the aqueous solution photocatalysis.

Nonlinear Absorption Features of Acid Blue 129 Dye in Polar Solvents: Role of Solvents on Solute Molecule.

This paper focuses the study of nonlinear absorption (NLA) features of anthraquinone dye namely, acid blue 129 with different polar solvents including ethanol, methanol, acetone, 1-proponal and DMSO. The acid blue 129 dye in polar solvents is characterized by UV-Visible absorption and fluorescence study. The NLA measurements of acid blue 129 dye is examined via open aperture (OA) Z-scan method employing at 650nm wavelength. The OA Z-scan curve of the experimental dye exhibits both saturable absorption (SA) and reveres saturable absorption (RSA) signature, which results from negative and positive NLA coefficient (β). The order of ground and excited state absorption cross-section is measured to be 10-22 m2 and 10-18 m2, respectively and proved the existence of RSA in acid blue 129 dye. The order of NLA coefficient and imaginary component of the third-order nonlinear susceptibility of acid blue 129 dye in polar solvents is calculated to be 10-3cm/W and 10-5 esu, respectively. The multi-parameter scale viz., Kamlet-Abboud-Taft is used to measure the influence of solvent parameters on solute molecule. The results from the experiments suggest that the acid blue 129 is a suitable candidate for nonlinear optical (NLO) applications.

Supercritical carbon dioxide (SC‐CO2) dyeing of cellulose acetate: An opportunity for a “greener” circular textile economy

AbstractThis article compares the dyeing of cellulose diacetate (cellulose‐based) and polyester fabrics using supercritical carbon dioxide (SC‐CO2) and aqueous media. The benefits of dyeing in SC‐CO2 were clearly demonstrated in laboratory‐based and pilot‐scale studies in terms of increased colour strength, uniformity, fastness and the absence of auxiliaries such as dispersing agents or surfactants. In addition, the “super‐levelling” nature of the SC‐CO2 medium was demonstrated in the reprocessing of polyester “waste textile” and the re‐use of the “locked‐in waste” colourant. The SC‐CO2 processing medium can be utilised to accurately colour “multiple life” polyester and cellulose acetate uniformly and to creatively tie‐dye polyester and cellulose acetate fabrics. Through SC‐CO2 fluid technology, we can envisage a viable waterless circular manufacturing and recycling/remanufacturing framework for the predominantly polyester global fibre market coupled to the sustainably sourced, biodegradable cellulose diacetate as a replacement for cotton. The key technical and commercial advantages being the use of a single solvent dye class for both polyester and the cellulose diacetate, saving on energy costs, integrated simpler processing, reduced water usage and associated efficient recycling. Further, repositioning the cellulosic fibre industry towards using sustainable forests is attractive in terms of improved land, water and environmental management.

Ammonium-Assisted Intercalation of Java Bentonite as Effective of Cationic Dye Removal

Modification of Java bentonite assists by the multi-step intercalation of sodium and ammonium ions under low-temperature preparation. The adsorbent was examined to remove rhodamine B and methylene blue dyes in an aqueous solvent. The analysis of structural changes conducted by XRD analysis showed the peak shifting from 19.89° to 16.1° and specific peak spectra FTIR of 2846.93 cm-1 due to increase basal spacing from ammonium intercalation. The total capacities of NH-bentonite, Na-bentonite, and Natural Bentonite adsorption to rhodamine B were 192.308 mg/g, 136.936 mg/g, and 116.279 mg/g, respectively, under acidic conditions. Furthermore, the total capacities of NH-bentonite, Na-bentonite, and Natural Bentonite adsorption to methylene blue were 270.27 mg/g, 158.73 mg/g, and 136.986 mg/g, respectively, under alkaline conditions. The adsorption mechanism described that the rhodamine B and methylene blue removal occurred endothermically, was feasible, and adhered to the kinetics model of pseudo-second-order and Langmuir isotherm. It concluded that the modified Java Bentonite from multi-step intercalation is affordable and effective as wastewater treatment.

Effects of Natural Dye Solvent Extraction on the Efficiency of Dye-Sensitive Solar Cells from the Leaf Biomass of Sandoricum koetjape and Syzygium samarangense

Effects of Natural Dye Solvent Extraction on the Efficiency of Dye-Sensitive Solar Cells from the Leaf Biomass of Sandoricum koetjape and Syzygium samarangense

Optical Behavior of Nile Red in Organic and Aqueous Media Environments

A simple model is proposed to calculate the dimerization constant of a dye in non-aqueous solvents. Alkan-1ols of the formula H–(CH2)n–OH are used to study the spectroscopic behavior of Nile Red dye. The number n varied from 1 to 8 to modulate the medium hydrophobicity. Generally, Nile red is used to localize lipid droplets within cells. This molecule is non-fluorescent in water and other polar solvents but undergoes fluorescence enhancement and large absorption and emission blue shifts in non-polar environments. The calculated equilibrium constants suggest that the aggregation process is solvent-assisted. The absorption and fluorescence emission spectra reveal a marked red shift, which is studied by breaking the wavelength of the maximum band into two terms, showing the contribution of the solvent and the effect of the dye concentration. Both contributions were investigated as a function of the number n, and it was found that alkan-1ols with large n tend to aggregate and produce a smaller red shift. Conversely, it was also noticed that short-chain alkan-1ols stabilize the excited state of the dye via H-bond and the red shift increases. The hydrophilicity of the medium was found to be modulated by adding pure water, in a controlled way, to the binary systems dye–H–(CH2)n–OH (n = 1–8). The quantification of solvent hydrophilicity is described with the ratio R = water moles/alcohol moles. From this investigation, we realized that the absorption spectra values are strictly connected with the R parameter. In this context, we realized that fluorescence emission spectra allow us to determine the adjustable parameters.

Determination of ink aging by two different methods

Ink age determination; based on the detection of changes in the structure of the ink on the document over time. These changes are degradation of dyes, evaporation of solvents and polymerization of resins. The time for these changes to ocur varies according to the structure of the ink and the environment in which the document stored. In this study, the age of the document was determined by analyzing the dyes and solvents in the structure of the ink that document was sent by the court in 2017. The phenoxyethanol was which found in the structure of the ink was detected by thermal desorption –gas chromatography-mass spectrometer while the determination of the dyes (crystal violet, methyl violet, tetramethyl pararosanil and Victoria blue) were determined by high pressure liquid chromatography-ultraviolet detector. Dye and relative solvent ratios were calculated and compared in age determination. It was discovered that the signature was produced after the writings by examining the ratio of CV/MV for the signature and personal name. Additionally, the presence of contamination from a different document was detected through phenoxyethanol analysis. The age of the document was determined using the V%-time curve, revealing that the signature was created between 3-7 months from the date of analysis.