Dye Disperse Red 1 Research Articles

Effect of Disperse Red 1 Azobenzene Dye Doping and Annealing on the Thermomechanical and Photomechanical Properties of PMMA Fibers

This work studies the effect of azobenzene dye Disperse Red 1 (DR1) doping and annealing on the thermomechanical and photomechanical properties of poly(methyl methacrylate) (PMMA) fibers. The mechanical properties are measured as a function of temperature, pump light intensity, and polarization. We find that doping with DR1 increases the stiffness and the glass transition temperature (Tg) of the PMMA fibers. Moreover, annealing below Tg decreases Young’s modulus and increases Tg. Finally, the photothermal heating contribution to the photomechanical response and the length change during laser exposure are determined in both unannealed and annealed plain PMMA and DR1-doped PMMA fibers. We find that photothermal heating is the dominant mechanism and the effect of photoisomerization is negligible. The temperature-dependent photomechanical efficiencies are also determined.

Photothermal and Reorientational Contributions to the Photomechanical Response of DR1 Azo Dye-Doped PMMA Fibers

This work is a comprehensive experimental and theoretical study aimed at understanding the photothermal and molecular shape-change contributions to the photomechanical effect of polymers doped with azo dyes. Our prototypical system is the azobenzene dye Disperse Red 1 (DR1) doped into poly (methyl methacrylate) (PMMA) polymer formed into optical fibers. We start by determining the thermo-mechanical properties of the materials with a temperature-dependent stress measurement. The material parameters, so determined, are used in a photothermal heating model—with no adjustable parameters—to predict its contribution. The photothermal heating model predicts the observations, ruling out mechanisms originating in light-induced shape changes of the dopant molecules. The photomechanical tensor response along the two principle axes in the uniaxial approximation is measured and compared with another independent theory of photothermal heating and angular hole burning/reorientation. Again, the results are consistent only with a purely thermal response, showing that effects due to light-induced shape changes of the azo dyes are negligible. The measurements are repeated as a function of polymer chain length and the photomechanical efficiencies determined. We find the results to be mostly chain-length independent.

Simple, fast, and ultrasensitive method for textile dye determination based on luminol electrochemiluminescence (ECL) inhibition

Textile dyes are considered micropollutants or emerging pollutants since they can be present in the environment at very low concentrations and show negative effects to human and environmental health. In this work, a luminol ECL inhibition sensor was successfully developed for detection of the textile dye Disperse Red 1 (DR1). Chitosan-Fe3O4 magnetic particles (MP) functionalized with luminol were mixed into a DR1 solution at different concentrations in the presence of H2O2. The mixture was dripped on the electrode surface, and measurements by linear sweep voltammetry and ECL were performed simultaneously. As a result, the ECL signal decreased with increasing DR1 concentration. This strategy exhibited good reproducibility and allowed us to determine DR1 at the very low detection limit of 0.070 pg mL−1. Also, there were good recoveries for detection of the textile dye in river water samples without the need of sample pretreatment. The ECL inhibition sensor has potential for application in the detection of a diversity of target molecules that could interact with luminol.

Comparative Study of Nano-Slot Silicon Waveguides Covered by Dye Doped and Undoped Polymer Cladding

Nonlinear optical dyes doped in optical polymer matrices are widely used for electro-optical devices. Linear optical properties change with dye concentration, which leads to a change in modal properties, especially in nano-structured integrated waveguides such as silicon slot-waveguides. Here, we investigate the influence of a nonlinear optical dye on the performance of a silicon-organic hybrid slot-waveguide. A simulation study of the modal and optical confinement properties is carried out and dependence of the structural parameters of the slot-waveguide and the organic cladding material is taken into account. As cladding material, a guest-host polymer system is employed comprising the nonlinear optical dye Disperse Red 1 (DR1) doped in a poly[methyl methacrylate] (PMMA) matrix. The refractive indices of doped and undoped PMMA were deduced from ellipsometric data. We present a guideline for an optimized slot-waveguide design for the fabrication in silicon-on-insulator technology giving rise to scalable, high-performance integrated electro-optical modulators.

Synthesis, characterization and application of nanoscale zero-valent iron in the degradation of the azo dye Disperse Red 1

In this work, a multivariate response surface methodology (RSM), was applied to analyze the effects of the synthesis variables that affect the reactivity of nanosized zero valent iron particles (NZVI), obtained by chemical reduction with sodium borohidride on the decoloration of azo dye Disperse Red 1 (DR1). Statistical analysis and data interpretation revealed that the generated model showed significant regression and fitting. The conditions that generated NZVI with higher reactivity correspond to [Fe 2+]:[BH4−] molar ratio=1:3, higher rates of reducing agent addition and lower pH (2–3). NZVI particles synthesized under the optimal conditions were characterized via XRD, BET surface area and electron microscopy. The results showed that the nanostructured material had composition, morphology and crystallinity typical of zero-valent iron, with BET surface area of ​​45m2g−1 and an average particle size of 60nm. NZVI yielded high color removal in fairly short time (around 98% in 10min). Latter combination with H2O2 allowed high mineralization.

Label-free impedimetric immunosensor for detection of the textile azo dye Disperse Red 1 in treated water

The development of methodologies to detect and quantify azo dyes in treated water is required because some of these dyes exhibit genotoxic activity, even at low concentrations. Here, the construction and characterization of an impedimetric immunosensor for determination of the textile azo dye Disperse Red 1 (DR1) by means of a label-free assay is reported. Anti-DR1 antibodies (Ab anti-DR1) were successfully coupled to glassy carbon electrode (GCE) surface by bonding using electrochemically generated activated carboxylic groups. The concentration of DR1 was measured by the increase in charge transfer resistance (RCT) when the immune reaction occurred, using Fe(CN)63−/4− as a probe. Electrochemical characterizations of the sensor by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed, and infra-red spectra were obtained to complement the electrochemical results showing immobilization of the antibodies. Under optimal conditions, the change in RCT presented a linear relationship with DR1 concentration in the range from 8.40 to 100nM, and the sensor provided low limit of detection (LOD=2.52nM) and quantification (LOQ=8.40nM). No significant interference from other azo dyes was observed. The performance of the immunosensor was evaluated using tap water spiked with 20.0nM DR1 and a satisfactory recovery of 98.5% was found. The proposed immunosensor is simple, relatively inexpensive, and shows good sensitivity for this application.

Occurrence and risk assessment of an azo dye – The case of Disperse Red 1

Water quality criteria to protect aquatic life are not available for most disperse dyes which are often used as commercial mixtures in textile coloration. In this study, the acute and chronic toxicity of the commercial dye Disperse Red 1 (DR1) to eight aquatic organisms from four trophic levels was evaluated. A safety threshold, i.e. Predicted No-Effect Concentration (PNEC), was derived based on the toxicity information of the commercial product and the purified dye. This approach was possible because the toxicity of DR1 was accounting for most of the toxicity of the commercial mixture. A long-term PNEC of 60 ng L−1 was proposed, based on the most sensitive chronic endpoint for Daphnia similis. A short-term PNEC of 1800 ng L−1 was proposed based on the most sensitive acute endpoint also for Daphnia similis. Both key studies have been evaluated with the new “Criteria for Reporting and Evaluating ecotoxicity Data” (CRED) methodology, applying more objective criteria to assess the quality of toxicity tests, resulting in two reliable and relevant endpoints with only minor restrictions. HPLC-MS/MS was used to quantify the occurrence of DR1 in river waters of three sites, influenced by textile industry discharges, resulting in a concentration range of 50–500 ng L−1. The risk quotients for DR1 obtained in this work suggest that this dye can pose a potential risk to freshwater biota. To reduce uncertainty of the derived PNEC, a fish partial or full lifecycle study should be performed.

Multi-scale biomarker evaluation of the toxicity of a commercial azo dye (Disperse Red 1) in an animal model, the freshwater cnidarian Hydra attenuata

Acute (24 h, 48 h, 72 h) and chronic (7 days) tests have been performed to evaluate the effects of the commercial azo dye Disperse Red 1 (DR1) using various biomarkers in the freshwater invertebrate Hydra attenuata. Morphological changes have been selected to calculate ecotoxicological thresholds for sublethal and lethal DR1 concentrations. A multinomial logistic model showed that the probability of each morphological stage occurrence was function of concentration, time and interaction between both. Results of oxidative balance parameter measurements (72 h and 7 days) suggest that polyps set up defense mechanisms to limit lipid peroxidation caused by DR1. DR1 exposure at hormetic concentrations induces increase of asexual reproductive rates. This result suggests (1) an impact on the fitness-related phenotypical traits and (2) trade-offs between reproduction and maintenance to allow the population to survive harsher conditions. Changes in serotonin immuno-labeling in polyps showing alterations in feeding behavior suggest that chronic DR1 exposure impaired neuronal processes related to ingesting behavior in H. attenuata. This ecotoxicity study sheds light on the possible serotonin function in Hydra model and reports for the first time that serotonin could play a significant role in feeding behavior. This study used a multi-scale biomarker approach investigating biochemical, morphological, reproductive and behavioral endpoints in Hydra attenuata. This organism is proposed for a pertinent animal model to assess ecotoxicological impact of pollutant mixtures in freshwater environment.

Monitoring ecotoxicity of disperse red 1 dye during photo-Fenton degradation

The present work assessed the ecotoxicity of the commercially available form of the azo dye Disperse Red 1 (DR1) and the main degradation products generated during photo-Fenton degradation. The acute toxicity tests with the microcrustacean Daphnia similis showed that toxicity increased after 10 min of treatment, when 35% of the original concentration of the dye has been degraded but without decrease in total organic carbon concentration (TOC). The increase of toxicity was a consequence of generation of degradation products of higher toxicity than DR1, which achieved maximum concentration after 10 min reaction. The structures identified using LC/MS indicated that most of the intermediates were formed after addition of hydroxyl radical to benzenic ring but the cleavage of azo bond was also observed. The intermediates were further degraded and toxicity was then reduced to non toxic levels after 45 min experiment, when 98% of the initial concentration of DR1 was degraded and mineralization achieved 55%. The results of this study showed that the textile dye DR1 can be degraded by photo-Fenton process with removal of acute toxicity to D. similis even with incomplete mineralization.

Thermal analyses of dye Disperse Red 1 grafted onto silica nanoparticles

Dye-grafted silica nanoparticles (GSiO2) were synthesized via a dual-step process involving, first, attachment of the organic dye Disperse Red 1 (DR1) to the coupling agent, 3-isocyanatopropyltriethoxysilane, by means of urethane bonds, and then grafting of the silylated-DR1 onto silica nanoparticles (~6 nm) prepared by hydrolysis and condensation of tetraethoxysilane in a sol–gel process. Dye-adsorbed silica nanoparticles (DSiO2) were also prepared for comparison, for which DR1 was bound only physically to silica instead of covalent bonds. The thermal behaviors of the formed GSiO2 and DSiO2 were examined by means of differential scanning calorimetry and thermal gravimetric analysis. The results showed that both the particle size and silica content have significant effects on the thermal behaviors of the dye-adsorbed and dye-grafted silica. Moreover, crystalline DR1 lost significantly its crystallinity after being adsorbed on silica, and became virtually amorphous after being grafted onto silica. The formed particles were UV-cured with a multifunctional acrylic monomer to yield color coatings on glass substrates. UV–visible spectra indicated that brightness and color saturation of the coating comprising GSiO2 could be maintained better than that comprising DSiO2 after heat treatment at 280°C.

Hepatotoxicity Assessment of the Azo Dyes Disperse Orange 1 (DO1), Disperse Red 1 (DR1,) and Disperse Red 13 (DR13) in HEPG2 Cells

During the dyeing process in baths approximately 10 to 15% of the dyes used are lost and reach industrial effluents, thus polluting the environment. Studies showed that some classes of dyes, mainly azo dyes and their by-products, exert adverse effects on humans and local biota, since the wastewater treatment systems and water treatment plants were found to be ineffective in removing the color and reducing toxicity of some dyes. In the present study, the toxicity of the azo dyes disperse orange 1 (DO1), disperse red 1 (DR1), and disperse red 13 (DR13) was evaluated in HepG2 cells grown in monolayers or in three dimensional (3D) culture. Hepatotoxicity of the dyes was measured using 3-(4,5-dimethylthiazol-2yl)2,5-diphenyltetrazolium (MTT) and cell counting kit 8 (CCK-8) assays after 24, 48, and 72 h of incubation of cells with 3 different concentrations of the azo dyes. The dye DO1 only reduced the mitochondrial activity in HepG2 cells grown in a monolayer after 72 h incubation, while the dye DR1 showed this deleterious effect in both monolayer and 3D culture. In contrast, dye DR13 decreased the mitochondrial activity after 24, 48, and 72 h of exposure in both monolayer and 3D culture. With respect to dehydrogenase activity, only the dye DR13 diminished the activity of this enzyme after 72 h of exposure in both monolayer and 3D culture. Our results clearly demonstrated that exposure to the studied dyes induced cytotoxicity in HepG2 cells.

Photonic crystals in polymers by direct electron-beam lithography presenting a photonic band gap

Direct lithography in electron-beam sensitive polymers was investigated to fabricate 2D-slab polymer-based photonic crystal structures. Polymethyl-methacrylate (PMMA) doped with azo dye Disperse Red 1 (DR1) chromophores was used as a test material to produce optimized low-index contrast photonic crystals presenting a photonic band gap for TE polarization. Extensive computational simulations of the full 3D-slab modes guided the design and fabrication strategy through optimization of the lattice structure, lattice parameter, hole size, and slab thickness. An exposure strategy that takes advantage of 100kV beam energy for deep lithography, and exposure control for multilevel pattern definition is presented, resulting in the high aspect ratio and verticality required to achieve a strong band gap effect. Finally, a method that enables a high-quality air-clad PMMA-DR1 to be fabricated and integrated with optical waveguides for characterization is presented, enabling successful observation of a photonic bandgap in a 2D-slab polymer photonic crystal.

Hydrogen-bonding between a dichroic dye and a liquid crystal-forming molecule, for application to LCDs

The performance of guest–host type liquid crystal displays (LCDs) is governed by the solubility and dissolution stability of dichroic dyes in the liquid crystal medium in guest–host kind of LCDs. The solubility and stability is influenced by hydrogen-bonding between the dye and the liquid crystal host. An earlier work was carried out to study the hydrogen-bonding behavior of 4-pentyl-4′-cyanobiphenyl (5CB) (liquid crystal), benzonitrile, and acetonitrile, with 1-hexanol in CCl4 using FTIR spectroscopy, ab initio and equation of state calculations [Ind. Eng. Chem. Res. 42 (2003) 1129]. To gain further thermodynamic understanding, hydrogen-bonding behavior of 5CB (liquid crystal), benzonitrile, and acetonitrile, with a dichroic dye Disperse Red 1 (DR1) {2-[ethyl[4-[(4-nitrophenyl)azo]phenyl]amino]ethanol} in CCl4 were studied in this work. In all three mixtures, -OH acts as a hydrogen-bond donor and -CN acts as hydrogen-bond acceptor. Based on FTIR analysis for DR1/acetonitrile, DR1/benzonitrile, and DR1/5CB, the enthalpies of hydrogen-bond formation are −24.2, −23.7, and −3.7kJ/mol, respectively; and the entropies of hydrogen-bond formation are −58.9, −58.1, and −0.4J/(molK), respectively. Though, for DR1/5CB, enthalpy of H-bonding is not too negative, the entropy of H-bonding is more favorable; hence the H-bonding appears to be entropically driven. Lattice fluid hydrogen-bonding (LFHB) parameters obtained from the spectroscopic data were observed to match well with the experimental trends. LFHB equation of state was then used to predict hydrogen-bonding for a wider range of conditions.

Aggregation of 3,5-dihydroxybenzyl alcohol based dendrimers and hyperbranched polymers, and encapsulation of DR1 in such dendritic aggregates

The aggregation behavior of 3,5-dihydroxybenzyl alcohol based dendritic polymers through intermolecular hydrogen bonding between periphery situated variable number of OH groups was studied using dynamic light scattering and transmission electron microscopy. Size of the aggregates was found to be dependent on the generation number of dendrimers: generations 1–3 form aggregates above critical aggregation concentration (cac), while higher generations (4–5) aggregate even at concentrations much lower than cac. Encapsulation of the dye disperse red 1 (DR1) into dendrimer aggregates was accompanied by a blue shift in the UV–Vis absorption spectrum of DR1.

Nonlinear refractive indices of polystyrene filmsdoped with azobenzene dye Disperse Red 1

Nonlinear refractive indices of polystyrene films containing azobenzene dye Disperse Red 1 (DR1) have been measured as a function of wavelength using the single beam Z-scan technique with a Fourier analysis of the transmittance time evolution. Although the C.W. excitation is carried out far from the absorption resonance region, the large nonlinear optical response has its origin in a thermal effect. We were able to find the thermal diffusivity coefficient of the sample.

Design and synthesis of ferroelectric liquid crystals. 22. side-by-side dimers for nonlinear optics

Abstract Possessing excellent processibility on silicon integrated circuits and a thermodynamically stable polar supermolecular structure, chiral smectic C (C*) ferroelectric liquid crystals (FLCs) are promising materials for use in ultra-fast (>500 MHz) integrated electro-optic modulators. In order to realize this promise, however, it is necessary to obtain FLC materials with values of the electronic second order nonlinear optical (NLO) susceptibility χ(2) larger than have been reported to date. One way to achieve this goal is to obtain orientation of “large β” organic functional arrays, composed of two rings with a conjugating spacer unit, along the polar axis in the C* phase. Such long molecular groupings, however, typically orient along the director in LC phases, normal to the C* polar axis. We present herein the results of the initial investigation of an approach for achieving large χ(2) in FLCs. In this case orientation of the prototypical large β chromophore found in the dye Disperse Red 1 (DR1) is...

Thermally stable and large second-order nonlinearity in poled silica films doped with Disperse Red 1 in high concentration

Solgel-processed silica films doped with the organic azo dye Disperse Red 1 (DR1) are prepared in a higher concentration than previously reported. Second-harmonic generation (SHG) from corona-poled films is measured with the Maker fringe technique with a Nd:YAG laser (1064 nm). The second-order nonlinear-optical coefficient is evaluated as d15 = 27 pm/V, d31 = 26 pm/V, and d33 = 120 pm/V, at a DR1 concentration of 2.2 × 1021/cm3. The nonlinearity is stable for at least 1000 h at 125 °C without any relaxation.