Aqueous Solution Research Articles

On the van der Waals Heteroepitaxy and Hydroxylation/Oxidation States of Au@Muscovite by Pulsed Laser Ablation in Water and Recovery in Aqueous KOH Solution

On the van der Waals Heteroepitaxy and Hydroxylation/Oxidation States of Au@Muscovite by Pulsed Laser Ablation in Water and Recovery in Aqueous KOH Solution

Osmotic and Activity Coefficients of Aqueous Lithium Sulfate Solutions within the Temperature Range 293.15–498.15 K to 40 MPa

Osmotic and Activity Coefficients of Aqueous Lithium Sulfate Solutions within the Temperature Range 293.15–498.15 K to 40 MPa

Degradation of pharmaceuticals and other emerging pollutants employing bi-metal catalysts/magnesium and/or (green) hydrogen in aqueous solution.

Contaminations by pharmaceuticals, personal care products, and other emerging pollutants in water resources have become a seriously burgeoning issue of global concern in the first third of the twenty-first century. As societal reliance on pharmaceuticals continues to escalate, the inadvertent introduction of these substances into water reservoirs poses a consequential environmental threat. Therefore, the aim of this study was to investigate reductive degradation, particularly, catalytic hydrogenation regarding model pollutants such as diclofenac (DCF), ibuprofen (IBP), 17α-ethinylestradiol (EE2), or bisphenol-A (BPA), respectively, in aqueous solutions at lab scale. Iron bimetals (zero valent iron, ZVI, and copper, Cu, or nickel, Ni) as well as zero valent magnesium (Mg, ZVM) in combination with rhodium, Rh, or palladium, Pd, as hydrogenation catalysts (HK), were investigated. Studies were executed through various short-term batch experiments, with multiple sample collections, over a total range of 120min. The results indicated that DCF was attenuated at over 90 % when exposed to Fe-Cu or a Fe-Ni bimetal (applied as a single model pollutant). However, when DCF was part of a mixture alongside with IBP, EE2, and BPA, the attenuation efficacy decreased to 79 % with Fe-Cu and 23 % with Fe-Ni. Conversely, both IBP and BPA exhibit notably low attenuation levels with both bimetals, less than 50 %, both deployed as single substances or in mixtures. No reaction (degradation) products could be identified employing LC-MS, but sometimes a release of the parent pollutant when applying an acetic acid buffer could be noted to a certain extent, suggesting adsorption processes on corrosion products such as iron hydroxide and/or oxides. Surprisingly, Mg in combination with Rh (Rh-HK) or Pd (Pd-HK) showed a significantly rapid decrease in the concentrations of DCF, EE2, and BPA, in part up to approximately 100 %, that is, within a few minutes only in part due to hydrogenation degradation reactions (related reaction products could actually be identified by LC-MS; adsorption processes were not observed here). Moreover, kinetic modeling of the DCF degradation with Mg-Rh-HK was conducted at different temperatures (15 °C, 20 °C, 25 °C, 35 °C) and varied initial concentrations (2.5mg/L, 5.0mg/L, 7.5mg/L, 10.0mg/L). The outcomes prove that the degradation of DCF at the Rh-HK's surface followed a modified first-order kinetics, most probably by catalytic hydrodehalogenation and subsequent hydrogenation of the aromatic moieties (molecular hydrogen was provided by the corrosion of Mg). From the determined reaction rate constants at four different temperatures, the activation energy was estimated to be 59.6kJ/mol by means of the Arrhenius equation what is in good agreement with similar results reported in the literature. This coupled hydrodehalogenation and hydrogenation approach may be upscaled into a new promising technical process for comprehensively removing such pharmaceuticals and similar pollutants in sewage plants in a single step, furthermore, even in combination with adsorption by activated carbon and/or ozonation which have already been established at some sewage plants in Switzerland and Germany recently.

Chemical Modification of Birch Bark (Betula L.) for the Improved Bioprocessing of Cadmium(II), Chromium(VI), and Manganese(II) from Aqueous Solutions

This study aimed to assess the sorption capacity of a natural sorbent, specifically birch bark (BB), and its modification using chemical reagents, including nitric and hydrochloric acid, sodium hydroxide, and chloride. The objective of the chemical modification was to enhance the sorption capacity of the heavy metals cadmium(II), chromium(VI), and manganese(II). The most effective modification for adsorbing cadmium and manganese from aqueous solutions was achieved by treating the sorbent with a 0.1 M sodium hydroxide solution (BBNa). Conversely, in the case of chromium, each modification adversely affected its adsorption by the sorbent. Concentrations of the solutions were analyzed using atomic absorption spectrometry at appropriate time intervals. The adsorption process was described using Langmuir, Freundlich, and Temkin isotherms. The Freundlich isotherm provided the best fit for cadmium and chromium (R2 = 0.988 and 0.986, respectively), while the Langmuir isotherm was most suitable for manganese (R2 = 0.996). The sorption capacity varied for each metal ion: Cd (II)—33.13 mg/g, Cr (VI)—35.98 mg/g, and Mn (II)—24 mg/g for the highest concentration tested. This study employed pseudo–first-rate order, pseudo–second-rate order model kinetics, and the Weber–Morris model to examine the adsorption kinetics. The pseudo–second-rate order kinetics demonstrated the best fit (R2 > 0.94) for each heavy metal, which underlines the process’s chemical nature.

Hydrothermally Produced Activated Carbon Impregnated with ZnO for the Adsorptive Removal of Toxic Pharmaceutical Contaminants from Aqueous Solution

This research explores the adsorption (AD) of diclofenac sodium (DS) onto a Hydrothermally produced activated carbon impregnated with ZnO (HTC-AC/ZnO) surface, considering various factors such as initial concentration (IC), adsorbent dose, contact time, and pH. The characterization of HTC-AC/ZnO was performed using X-ray diffractometer (XRD), scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), and nitrogen physisorption spectroscopy (BET). Tests were conducted with different adsorbent doses (0.5–4 g/L) at 303 K and various initial diclofenac concentrations (ranging from 50 mg/L to 250 mg/L) to observe their effects. Additionally, pH values were altered from 2 to 12 to study their influence on AD. Kinetic studies, thermodynamic studies, and AD isotherm models were examined. The Temkin isotherm model (TIM) was found to be the most accurate for DS-AD on HTC-AC/ZnO. For DS-AD on HTC-AC/ZnO, pseudo-first-order models (PFOM), intraparticle diffusion model (IPDM), and pseudo-second-order models (PSOM) were applied, with a correlation coefficient of 0.945, indicating a good fit for PFOM. The kinetics suggested rapid adsorption. Notably, the HTC-AC/ZnO composite exhibited consistent AD characteristics across four consecutive cycles, with a removal efficiency exceeding 99.38%. This suggests that HTC-AC/ZnO is an appropriate and economically viable adsorbent for the elimination of DS from water-based solutions. The investigation provides compelling evidence that HTC-AC/ZnO is a viable adsorbent for the effective elimination of DS from water sources.

Utilizing Rapid Hydrogen Peroxide Generation from 6-Hydroxycatechol to Design Moisture-Activated, Self-Disinfecting Coating.

A coating that can be activated by moisture found in respiratory droplets could be a convenient and effective way to control the spread of airborne pathogens and reduce fomite transmission. Here, the ability of a novel 6-hydroxycatechol-containing polymer to function as a self-disinfecting coating on the surface of polypropylene (PP) fabric was explored. Catechol is the main adhesive molecule found in mussel adhesive proteins. Molecular oxygen found in an aqueous solution can oxidize catechol and generate a known disinfectant, hydrogen peroxide (H2O2), as a byproduct. However, given the limited amount of moisture found in respiratory droplets, there is a need to enhance the rate of catechol autoxidation to generate antipathogenic levels of H2O2. 6-Hydroxycatechol contains an electron donating hydroxyl group on the 6-position of the benzene ring, which makes catechol more susceptible to autoxidation. 6-Hydroxycatechol-coated PP generated over 3000 μM of H2O2 within 1 h when hydrated with a small amount of aqueous solution (100 μL of PBS). The generated H2O2 was three orders of magnitude higher when compared to the amount generated by unmodified catechol. 6-Hydroxycatechol-containing coating demonstrated a more effective antimicrobial effect against both Gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria when compared to unmodified catechol. Similarly, the self-disinfecting coating reduced the infectivity of both bovine viral diarrhea virus and human coronavirus 229E by as much as a 2.5 log reduction value (a 99.7% reduction in viral load). Coatings containing unmodified catechol did not generate sufficient H2O2 to demonstrate significant virucidal effects. 6-Hydroxycatechol-containing coating can potentially function as a self-disinfecting coating that can be activated by the moisture present in respiratory droplets to generate H2O2 for disinfecting a broad range of pathogens.

Cu (II)-based metal-organic framework functionalized with graphene oxide as a sorbent for the dispersive micro-solid-phase extraction of losartan potassium from water

AbstractIn this study, a new metal–organic framework (MOF) based on copper (II) functionalized with graphene oxide (MOF-Cu@GO) was successfully synthesized and applied as an efficient sorbent for dispersive micro-solid phase extraction (D-μSPE) of losartan potassium (LP) from water. The MOF-Cu@GO sorbent was characterized using DRX, FTIR, XPS, TGA, RAMAN, BET, SEM, EDX, and potential Z. The influence of different parameters in the D-μSPE method was studied and optimized using the fractional factorial design 25–1 and central composite design. The results indicated that the adsorption process was spontaneous and endothermic followed the pseudo-second order model kinetics and the Freundlich isotherm. The maximum adsorption capacity of MOF-Cu@GO sorbent was 415 mg g−1. The adsorption mechanism proposed of LP onto MOF-Cu@GO proceeded via electrostatic interaction, hydrogen bonds, unsaturated sites of the ligand, and π-π interactions. The microextraction procedure was followed by determination of LP with high performance liquid chromatography (HPLC–UV-Vis). Under optimized conditions, the limits of detection and quantitation were found to be 25 and 80 ng ml−1 respectively, the method exhibited a linear response (r = 0.998) in the concentration range of 0.1–50 µg ml−1 of LP, with a relative standard deviation less than 2% (n = 5). The D-μSPE method showed preconcentration factor of 684.9 and high percentage of LP extraction of 99.78% ± 2.62, the accuracy of the method was demonstrated by studying the recovery of LP from water samples of 100.3 ± 1.06. The material obtained can be used up to 3 cycles with time for the sorption and determination of 30 min indicating good stability and reusability. The MOF-Cu@GO proposed is an efficient and fast sorbent in the D-μSPE for determination of LP from aqueous solutions.

Hexavalent chromium adsorption from aqueous solution utilizing activated carbon developed from Rumex abyssinicus

The indiscriminate release of chromium-saturated effluent into water bodies has raised concerns regarding its effect on human health and environmental ecology. Therefore, this research aimed to remove hexavalent chromium from an aqueous solution utilizing activated carbon developed from Rumex abyssinicus. The adsorbent was prepared through chemical impregnation with H3PO4 and then thermally activated at 500 °C for 2 h. The optimization of the adsorption experiments was performed using the Box‒Behnken approach of response surface methodology. The characterization of the prepared activated carbon revealed good quality in terms of its amorphous structure, maximum specific surface area of 1722.9 m2/g and porous surface. Furthermore, the optimization results showed that a maximum removal efficiency of 95.97 % was attained at an optimum working pH of 3, a contact time of 60 min, an initial chromium concentration of 70 mg/L and an adsorbent dosage of 0.6 mg/100 mL. The Langmuir isotherm model was found to have the best fit with the experimental data. Moreover, the kinetics study revealed that a pseudo-second-order model fit the data best, indicating the occurrence of chemisorption. Overall, this study suggested that Rumex abyssinicus could be an effective adsorbent for removing hexavalent chromium from aqueous solutions.

Enhanced Near-infrared Phosphorescent Emission Modulated by Clipping of Metallotweezers in Aqueous Media.

Near-infrared phosphorescent materials have received significant attention due to their potential applications in bioimaging and diagnostics. Although, many types of organic phosphors with near-infrared emission have been developed, the low phosphorescence efficiency in aqueous solution hampers their practical applications in biological systems. Hence, there is an urgent need to develop near-infrared phosphorescent materials with high emission efficiency in aqueous media. Metallotweezers, based on d8 transition metal complexes, emerge as the potential candidates for realizing this objective. Specifically, metallotweezers, featuring two positively charged platinum(II) terpyridine and neutral gold(III) diphenylpyridine pincers on diphenylpyridine spacer, have been designed and synthesized, respectively. The pre-organization effect, rendered by the rigid spacer, enables the resulting metallotweezers to complex with each other, resulting in the formation of clipping complex. The synergistic rigidifying and shielding effects of clipping structure results in enhanced phosphorescent emission intensity. Concurrently, due to phase segregation between the clipping units and the polyethylene glycol tail, the clipping complex undergoes self-assembly in aqueous solution, resulting in phosphorescent emission in the near-infrared region. Overall, non-covalent clipping of metallotweezers illustrated in this study presents a new and effective approach toward near-infrared phosphorescent materials.

When Tautomers Matter: UV-Vis Absorption Spectra of Hypoxanthine in Aqueous Solution from Fully Atomistic Simulations.

The UV-Vis spectrum of the solvated purine derivative Hypoxanthine (HYX) is investigated using the Quantum Mechanics/Fluctuating Charges (QM/FQ) multiscale approach combined with a sampling of configurations through atomistic Molecular Dynamics (MD) simulations. Keto 1H7H and 1H9H tautomeric forms of HYX are the most stable in aqueous solution and form different stable complexes with the surrounding water molecules, ultimately affecting the electronic absorption spectra. The final simulated spectrum resulting from the combination of the individual spectra of tautomers agrees very well with most of the characteristics in the measured spectrum. The importance of considering the effect of the solute tautomers and, in parallel, the contribution of the different solvent arrangements around the solute when modeling spectral properties, is highlighted. In addition, the high quality of the computed spectra leads to suggesting an alternative way for acquiring tautomeric populations from combined computational/experimental spectra.

Self-assembly of the porphyrin monomer on the surface of Fe/graphene material: a novel sensing material for the detection of chloramphenicol antibiotic in aqueous solution.

Currently, electrochemical sensors are in the process of being developed and widely used in various fields, and new materials are being explored to enhance the precision and selectivity of the sensors.The Fe/graphene nanoparticles were synthesized utilizing a green approach, wherein leaf extract was employed as the reducing agent. The resulting materials underwent comprehensive characterization utilizing a range of contemporary techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy. The findings of the study revealed that the nanocomposites of Fe/graphene/porphyrin comprised zero-valent iron nanoparticles, exhibiting an average particle size ranging from 15 to 60 nm. These nanoparticles were seen to be evenly dispersed across the graphene sheets. The presence of nanostructure porphyrin nanofibers, measuring 20 nm in diameter, was also shown to exhibit strong integration with the surface of the Fe/graphene nanomaterials. The electrochemical properties of the Fe/graphene/porphyrin nanocomposite were also investigated, demonstrating that the prepared material could be effectively employed as a sensing electrode in the electrochemical sensor for detecting Chloramphenicol (CAP) through CV, EIS, and DPV techniques using a three-electrode electrochemical system. Under optimal conditions, Fe/graphene/porphyrin exhibited a high current response when detecting CAPs.

Protector-free, non-plasmonic silver quantum clusters by femtosecond pulse laser irradiation: in situ binding on nanocellulose filaments for improved catalytic activity and cycling performance.

This study introduces a new, facile method to synthesize silver clusters from aqueous silver ion solution by using high intensity femtosecond pulse laser irradiation. The particles obtained in the absence of reducing or capping agents are 1-17 nm in size and presented quantum properties, as characterized by fluorescence, but did not exhibit plasmon signals, which is not a common characteristic of conventional silver nanoparticles. In a further development, small silver quantum clusters (∼1 nm) were bound in situ to wet-spun filaments of cellulose nanofibrils by pulsed laser irradiation. The obtained hybrid filaments as well as free silver quantum clusters revealed a catalytic activity remarkably higher than that of free gold quantum clusters; moreover, the hybrid filaments were found to show improved stability and cycling performance for silver-based catalysis. The present results indicate the potential of femtosecond laser irradiation to generate clusters as well as hybrid systems with excellent performance and reactivity.

Thixotropic Composite Hydrogel Electrode Composed of a Polymer Hydrogelator and Water-Dispersive Tungsten Oxide Flat Microparticles.

Here, we introduce an organic/inorganic composite hydrogel as a versatile gel electrode material. This composite hydrogel was formed by simply mixing an aqueous solution of flat microparticles of tungsten oxide, exhibiting superior water dispersibility, with a hydrogel composed of a water-soluble polyaramide-based polymer hydrogelator. The resulting composite hydrogel exhibited uniform dispersion of tungsten oxide flat particles throughout the hydrogel matrix, supplementing the structure formed by the polymer hydrogelator. It maintained the gel-forming capability and thixotropic behavior inherent to the polymer hydrogelator while showcasing the electrochemical characteristics of tungsten oxide. With its spreadability and applicability to various electrode shapes, a composite hydrogel is presented as a potential spreadable gel electrode material.

Swift and quantitative naked-eye detection of cyanide: A dual-mode approach using an ICT-based colorimetric and ratiometric fluorescent chemodosimeter

A chemodosimeter (1) based on dicyanovinyl with a strong intramolecular charge transfer (ICT) mechanism has been devised for the selective and sensitive detection of cyanide (CN−) in a tetrahydrofuran aqueous solution. In polar solvents, chemodosimeter 1 exhibits robust ICT-induced emission; however, in the solid state, its fluorescence weakens owing to the formation of molecular aggregates prompted by intermolecular π–π interactions. The colorimetric and ratiometric fluorescent changes observed in the chemodosimeter upon exposure to CN− result from the incorporation of CN− at the β-conjugated site of the dicyanovinyl moiety of chemodosimeter 1, effectively hindering the ICT process. This alteration is supported by 1H NMR titration experiments and density functional theory calculations, which corroborate the cyanide-induced ICT on–off switching mechanism. The detection limit of chemodosimeter 1 (5.8 × 10−7 M) for CN− falls below the maximum allowable level of cyanide in drinking water (1.9 × 10−6 M), as established by the World Health Organization. Test strips utilizing chemodosimeter 1 offer a potential solution for swift and quantitative naked-eye detection of CN− in real-time scenarios. Moreover, chemodosimeter 1 was effectively employed for detecting cyanide in actual environmental water samples.

Surface modified PLGA nanoparticles of gabapentin: Biodistribution and pharmacodynamic investigation via intranasal route

Epilepsy is a chronic condition and is caused by abnormal electrical conduction by nerve cells. It can affect people from different age groups. The prime objective of epilepsy therapeutics is the targeted and sustained release of drugs at the site of action i.e. in the brain. In the present study, PLGA nanoparticles of gabapentin, coated with Polysorbate 80 were prepared with the aim of delivering the drug to the brain through the nasal route. The said nanoparticles were formulated by the method of double emulsion and solvent evaporation. Thereafter, the prepared nanoparticles were characterized for particle size, Zeta potential, and Surface morphology of the nanoparticles was evaluated by SEM &TEM In vitro release in PBS (pH 7.4) and SNF (pH 5.5). In addition, FTIR and DSC techniques were used to confirm the P80 coating around the nanoparticle's surface. In vitro, cell assays like Cytotoxicity studies, and quantitative and qualitative cell uptake studies were studied on Neuro-2a cells. The nasal mucosa of the goat was used to perform histopathological studies to evaluate the toxicity of nanoparticles. A biodistribution study was performed on Swiss albino mice and the results showed that the concentration of the drug reaching the brain in the case of P80 modified nanoparticles was maximum as compared to Plain PLGA nanoparticle, and aqueous solution of the drug. Pharmacodynamic studies were performed to assess the delay in different phases of convulsion and the results showed that the modified nanoparticles of gabapentin were able to significantly delay the episodes of convulsion. Overall, results demonstrate that modified nanoparticles are potential drug carriers in the brain for the management of epilepsy.

Physiological quality of sunflower seeds under water stressed conditions

Water is one of the factors that most influences the seed germination process; however, its excess can cause injuries to cell membranes due to rapid imbibition. On the other hand, water restriction limits seed germination, promoting a reduction in cell water potential that disrupts physiological and metabolic reactions. Thus, the objective of this study was to evaluate the physiological quality of sunflower seeds subjected to water stress induced by polyethylene glycol 6000 (PEG 6000). The experimental design used was completely randomized, consisting of six treatments consisting of osmotic potentials (0; -0.3; -0.6; -0.9; -1.2; and -1.5 MPa) simulated with aqueous solutions of PEG 6000. Germination, radicle protrusion, first count, germination speed index, abnormal seedlings, shoot length, and root length were evaluated. Water stress induced by PEG 6000 solutions affects the physiological quality of sunflower seeds, being proportional to the reduction of osmotic potential. Germination and seed vigor decrease under water stress conditions from an osmotic potential of -0.4 MPa, with the most negative potentials (-1.2 and -1.5 MPa) preventing seed germination.

Effect of Methyl Violet to Mulberry Silkworm Some Breeds Eggs

To liquidate the larvae, the methyl violet (C24H28N3Cl), used against fungal diseases in fish farming, was used. The goal is to establish physiological responses in different phases of development after treating local and introduced mulberry silkworm breeds of with aqueous solutions of methyl violet. Exogenous exposure to eggs led to the formation of a negative reaction. It has been established that treatment of silkworm eggs with water and a 0.001% solution of methyl violet (from October 20 to November 15, 2018) reduces the weight of the silk layer of cocoons with statistical accuracy by 33.0% (−78.5 mg) and 22.5% (−49 .0 mg) respectively (p<0.001). A negative effect also occurs in other physiological indicators: there is a difference in the weight of caterpillars, cocoons and pupae, and a slight deviation occurs in the weight of caterpillars before cocooning in the aquatic version. The results of this research can be used in developing issues such as identifying more stable and promising mulberry silkworm breeds in the conditions of Azerbaijan, as a prerequisite for predicting the successful introduction of mulberry silkworm.

Tribocorrosion Evaluation of AISI 431 Coated With Tungsten Oxynitride

Abstract Tribocorrosion is a phenomenon present in a wide variety of processes; hence, understanding the tribocorrosion behavior of different systems is essential to being able to design robust and reliable systems. This has led us to investigate the tribocorrosion behavior of AISI 431 steel, a stainless steel commonly used for manufacturing mechanical pieces. The response to tribocorrosion was evaluated for the AISI 431 steel in contact with an aqueous solution of citric acid, a solution commonly used in the food industry. The tests were carried out using samples of steel uncoated and coated with tungsten oxynitride in a pin-on-disc configuration using a tailored tribocorrosion cell. The uncoated AISI 431 presented good wear and corrosion resistance but presented tribocorrosion degradation, where the growth of the passivation film and the mechanical removal of such film were the driving factors for the tribocorrosion process. Furthermore, when the steel was coated with the tungsten oxynitride film, we found that the surface presented a better resistance to wear, corrosion, and tribocorrosion. Such findings open a great opportunity for the use of these types of coatings to protect systems against tribocorrosion.

One-Stone-for-Two-Birds Method to Improve the SnO2 Layers for High Power-per-Weight Flexible Perovskite Solar Cell Mini-modules.

Maintaining the power conversion efficiency (PCE) of flexible perovskite solar cells (fPSCs) while decreasing their weight is essential to utilize their lightweight and flexibility as much as possible for commercialization. Strengthening the interfaces between functional layers, such as flexible substrates, charge transport layers, and perovskite active layers, is critical to addressing the issue. Herein, we propose a feasible and one-stone-for-two-birds method to improve the electron transport layer (ETL), SnO2, and the interface between the ETL and perovskite layer simultaneously. In detail, poly(acrylate ammonium) (PAAm), a low-cost polymer with a long chain structure, is added into the SnO2 aqueous solution to reduce the aggregation of SnO2 nanoparticles, resulting in the deposition of a conformal and high-quality ETL film on the tin-doped indium oxide film surface. Simultaneously, PAAm addition can effectively regulate the crystallization of the perovskite films, strengthening the interface between the SnO2 film and the buried surface of the perovskite layer. The outstanding PCEs of 22.41% on small-scale fPSCs and 18.54% on fPSC mini-modules are among the state-of-the-art n-i-p type fPSCs. Moreover, the fPSC mini-module on the 20 μm-thick flexible substrate shows a comparable PCE with that of the fPSC mini-module on the 125 μm-thick flexible substrate, exhibiting a high power-to-weight of 5.097 W/g. This work provides an easy but essential direction for further applications of fPSCs in diverse scenarios.

Tilted Bragg grating in a glycerol-infiltrated specialty optical fiber for temperature and strain measurements

In this Letter, we propose an in-line tilted fiber Bragg grating sensor for temperature and strain measurements. The grating is inscribed in a specialty optical fiber using tightly focused femtosecond laser pulses and the line-by-line direct writing method. Beside the central core in which the grating is produced, a hollow channel filled with glycerol aqueous solution significantly improves the sensitivity of the fiber cladding modes due to its high thermo-optic coefficient. We show that the temperature sensitivity of the core mode is 9.8 pm/°C, while the one of the cladding modes is strongly altered and can reach −24.3 pm/°C, in the investigated range of 20–40°C. For the strain measurement, sensitivities of the core mode and the cladding modes are similar (∼0.60 pm/με) between 0 and 2400 με. The significative difference of temperature sensitivity between the two modes facilitates the discrimination of the dual parameters in simultaneous measurements.