Rod-like Morphology Research Articles

Investigating the Effect of Nano-Crystalline Cellulose in Nitrile Butadiene Rubber Matrix for Improved Thermo-Mechanical Properties

The escalating demand for sustainable rubber products has spurred research into alternative reinforcing fillers, driven by concerns regarding the detrimental effects of using conventional fillers like carbon black and silica. In this investigation, nano-crystalline cellulose (NCC), derived from micro crystalline cellulose (MCC), sourced from sugarcane bagasse via acid hydrolysis, serves as a bio-filler to reinforce Nitrile Butadiene Rubber (NBR) matrices. NBR-NCC nano-composites were prepared using a two-roll mill, varying NCC from 1–5 parts per hundred rubber matrices, followed by hot press curing. NCC and NBR-NCC nano-composites were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), curing characteristics, thermo-mechanical testing, thermal aging and motor oil resistance. Chemical interactions between the NCC and NBR matrix were verified with FTIR. The SEM images of the NCC showed a combination of rod-like and spherical morphologies and a homogenous dispersion of NCC in NBR-NCC nano-composites with some agglomeration, notably at higher percentages of NCC. It is shown that the cure time decreases with increasing NCC loading which mimics a shorter industrial production cycle. The results also showed an increase in tensile strength, hardness, oil resistance and a rise in degradation temperature when compared to NBR at approximately 34%, 36%, 38% and 32 °C, respectively, at 3 phr NCC loading. Furthermore, NBR-NCC nano-composites showed a lower decrease in mechanical properties after aging when compared to NBR. The findings of this research suggest that the NBR-NCC nano-composites may find applications in high oil resistance seals and rubber gloves where higher thermal stability is strictly required.

Deep-sea fish reveal alternative pathway for vertebrate visual development.

Vertebrate vision is accomplished by two phenotypically distinct types of photoreceptors in the retina: the saturation-resistant cones for the detection of bright light and the highly sensitive rods for dim light conditions [1]. The current dogma is that, during development, all vertebrates initially feature a cone-dominated retina, and rods are added later [2, 3]. By studying the ontogeny of vision in three species of deep-sea fishes, we show that their larvae express cone-specific genes in photoreceptors with rod-like morphologies. Through development, these fishes either retain this rod-like cone retina ( Maurolicus mucronatus ) or switch to a retina with true rod photoreceptors with expression of rod-specific genes and transcription factors ( Vinciguerria mabahiss and Benthosema pterotum ). In contrast to the larvae of most marine fishes, which inhabit the bright upper layer of the open ocean, the larvae of deep-sea fishes occur deeper, exposing them to a dimmer light environment [4-7]. Spectral maxima predictions from molecular dynamics simulations and environmental light estimations suggest that using transmuted photoreceptors that combine the characteristics of both cones and rods maximises visual performance in these dimmer light conditions. Our findings provide molecular, morphological, and functional evidence for the evolution of an alternative developmental pathway for vertebrate vision.

Ultrastable hierarchically porous nucleotide-based MOFs and their use for enzyme immobilization and catalysis

Immobilization of free enzymes facilitates their recovery and reuse, while also enhances their enzymatic characteristics. Hierarchically porous metal-organic frameworks (HP-MOFs) are promising candidates for enzyme immobilization. However, fabrication of HP-MOFs with more kinds of components as ligands is still a challenge. Herein, ultrastable crystalline MOFs with micro-, meso- and macroporous structure were constructed using guanosine 5′-monophosphate (GMP) as organic ligand through templated emulsification method. HP-MOFs crystals with the near rhomb-like, rod-like and slab-like morphology were interestingly obtained from Zn2+, Cu2+ and Cd2+ respectively. The HP-MOFs immobilized enzymes exhibited an enhanced enzymatic activity and stability. In addition, the immobilized CALB (Candida antarctica lipase B) showed great glycerolysis and esterification performances for glycerides preparation, with diacylglycerols (DAG) content over 60 wt% and triacylglycerols (TAG) content over 90 wt% obtained respectively from glycerolysis and esterification. Moreover, it retained 82.32 % of its initial glycerolysis activity after six cycles of reuse in glycerolysis. The present study will provide clues and show new horizons to explore new organic ligands for HP-MOFs fabrication, as well as to expand the applications of HP-MOFs and their supported enzymes.

Atomically dispersed Ru on flower-like In2O3 to boost CO2 hydrogenation to methanol

Metal-based catalysts are prevalent in the CO2 hydrogenation to methanol owing to their remarkable catalytic activity. Herein, Ru/In2O3 catalysts with different morphologies obtained by doping Ru into In2O3 with irregular, rod-like, and flower-like morphologies are used for catalytic CO2 hydrogenation to methanol. Results indicate that the flower-like Ru/In2O3 (Ru/In2O3-F) exhibits higher catalytic performance than Ru/In2O3 with other morphologies, achieving a 12.9% CO2 conversion, 74.02% methanol selectivity, and 671.36 mgMeOH·h−1·gcat−1 methanol spatiotemporal yield. Furthermore, Ru/In2O3-F maintains its catalytic stability over 200 h at 5 MPa and 290 °C. The promotional effect mainly stems from the fact that electronic structure of Ru can be effectively adjusted by modulating the morphology of In2O3. The strong interaction between atomically dispersed Ru and In2O3-F enhances the structural stability of Ru, inhibiting the agglomeration of the catalyst during the reaction process. Furthermore, density-functional theory calculations reveal that highly dispersed Ru atoms not only perform efficient and rapid electronic gain and loss processes, facilitating the catalytic activation of H2 into H intermediates. It also enables the generated reactive H to rapidly overflow to the surrounding In sites to participate in CO2 reduction. These findings provide a theoretical basis for the development of high-performance catalysts for CO2 hydrogenation.

Folic acid functionalized Ag@MOF(Ag) decorated carboxymethyl starch nanoparticles as a new doxorubicin delivery system with inherent antibacterial activity

Considering the benefits of controlled drug delivery in cancer treatment, as well as the importance of biological macromolecules in this area, herein, the pre-synthesized carboxymethyl starch (CMS) was converted to CMS nanoparticles (CMS NPs) in one easy nanoprecipitation way. Thereafter, the Ag@MOF(Ag) was in situ synthesized in the presence of pre-prepared CMS NPs (CMS NPs/Ag@MOF(Ag)). Eventually, the functionalization with folic acid (FA) obtained the CMS NPs/Ag@MOF(Ag)-FA. The success of the accomplished process was approved by doing several techniques, including FT-IR, XRD, EDX, AFM, etc. The SEM analysis showed a combination of rod-like and spherical-like morphology for the fabricated bio-nanocomposite. The generated CMS NPs/Ag@MOF(Ag)-FA with a surface area of 10.595 m2/g displayed a pore size of 13.666 nm and 82.99 % of doxorubicin (DOX) loading efficiency (DOX@CMS NPs/Ag@MOF(Ag)-FA). The 38.46 % and 58.19 % of loaded DOX were released respectively within 240 h at pH 7.4 and pH 5.0, referring to the pH-responsivity of the constructed system. 27.25 % of inhibitory effects on HeLa cells were obtained for the drug-loaded bio-nanocomposite. The CMS NPs/Ag@MOF(Ag)-FA also displayed an inherent antibacterial activity towards two common gram-negative and gram-positive bacteria. All of these results can contribute to developing polysaccharide-based porous systems in controlled cancer therapy.

Smartphone-enabled composite of cellulose nanocrystals for rapid and selective mercury detection in cosmetics and water: insights from density functional theory studies

ABSTRACT The pervasive contamination of cosmetics and water with mercury ions (Hg(II)) poses severe health risks, driving the need for efficient methods for in situ detection and removal of it. Our study showcases a groundbreaking composite material that combines cellulose nanocrystals (CNCs) and smartphones for the purpose of rapid and selective mercury detection. The CNCs exhibit a distinctive rod-like morphology, presenting a high surface area that facilitates the accommodation of the Hg(II) ion probe, 4-(dimethylamino)phenyl)methanethione (DPM). This interaction leads to a distinct colour change from yellow to green, visible to the naked eye, enabling straightforward visual detection. Our composite is highly sensitive, with a limit of detection (LOD) of 1.76 × 10 − 8 M using digital image analysis and 3.6 × 10 − 8 M using spectrophotometric methods. These values are significantly below the safe drinking water guidelines set by the World Health Organization (WHO). Density functional theory (DFT) calculations were used to understand how Hg(II) ions interact with the DPM-CNC composite. These calculations confirmed that the material has a strong affinity for Hg(II) ions and demonstrated its selective detection capabilities. The DPM-CNC composite’s low detection threshold, rapid response time, and ease of regeneration make it a potent candidate for practical applications in mercury monitoring. This composite is a robust and reusable solution for real-time visualisation and quantification of mercury ions. It only requires 10 mg of material for effective measurements. It enhances safety in cosmetic products and water.

Sustainable extraction of cellulose nanocrystals from empty palm oil bunches via low-acid hydrolysis

The increasing production of empty palm oil bunches (EPOB) poses significant environmental challenges due to waste accumulation. This study aims to convert EPOB into valuable cellulose nanocrystals (CNCs) through a sustainable extraction process utilizing low-acid concentration. The extraction method involves three key steps: alkalization, bleaching, and hydrolysis with 30 % sulfuric acid. The results indicate a high α-cellulose content of 87.04 % and an increase in crystallinity of the extracted CNCs to 60.28 %, as confirmed by X-ray diffraction analysis. The CNCs exhibit a rod-like morphology with an average diameter of 1.66 nm and a length of 9.85 nm. This research demonstrates that EPOB can be effectively transformed into high-quality CNCs, providing a cost-effective and environmentally friendly alternative for utilizing agricultural waste. The findings support the potential application of CNCs in various fields, including biodegradable materials and coatings, contributing to sustainability in the palm oil industry.

Enhancement of charge storage capacity in two-leg pseudo-spin ladder CaCu2O3 compound through Li-doping

Nanostructured 2-leg pseudo spin-ladder compound CaCu2O3 has been synthesized by chemical co-precipitation method and a significant improvement in its charge storage capacity has been realized through Li-doping. The fabricated electrode based on Li-doped CaCu2O3 exhibited higher specific capacitance of 321.26 F/g at 1.5 A g-1 when compared to that of 205.45 F/g for undoped CaCu2O3 system. Moreover, the electrode revealed an excellent cyclic stability (5000 cycles) with capacitance retention of 91.96 % of its initial value. An asymmetric supercapacitor fabricated using nano-flakes shaped Li-CaCu2O3 and activated carbon showed a notable energy density of 36.72 Wh/kg and power density of 1406 W/kg which maintains the energy density of 7.81 Wh/kg even at higher power density of 7031.25 W/kg. Among various Li-doped samples, 2.5 wt.% Li-CaCu2O3 exhibited the best storage capacity. This improvement has been attributed to the intrinsic off-stoichiometric (Ca0.86Cu2.14O2.93) and spin ladder structure of CaCu2O3 which allows Li to intercalate and improve the storage performance. Moreover, higher reactive surface area due to nano-flake morphology and porous structure of Li-CaCu2O3 may enhance the permeability of electrolytic ions, thereby improving the performance of the fabricated supercapacitor compared to undoped CaCu2O3 with rod-like morphology. These findings underscore the potential of Li-CaCu2O3 as a promising candidate material for fabricating supercapacitor devices.

Enhancement of antimicrobial properties and cytocompatibility through silver and magnesium doping strategies on copper oxide nanocomposites

In the present study, silver (Ag), magnesium (Mg), and the various molar ratios of Ag:Mg-doped copper oxide nanocomposites (CuO NCs) were synthesized by the co-precipitation method. The CuO NC samples calcined at 500 °C were further analyzed for their morphological, structural, functional, and optical properties. Adding single and dual doping increased the pristine CuO band gap from 1.28 to 1.50 eV. The Ag and Mg metal peaks were revealed in the Fourier transform infrared (FTIR) analysis, while an elevated Mg band was observed in all Mg-doped samples in the Raman results. All CuO NCs showed a monoclinic crystalline structure, flake, and rod-like morphologies. Microbes of Bacillus subtilis, Shigella dysenteriae, and Candida albicans were tested against different concentrations of CuO NCs. Better results for all tested microbes were observed with the 2 mg concentration. The high cytotoxicity effect was observed in the pristine and Cu:Ag (94:6) sample, and other CuO NCs, which demonstrated over 80 % viability in RAW 246.7 cells at a concentration of 0.5 µg/ml. Remarkably, over 94 % cell viability at 0.5 µg/ml was achieved with the Cu:Ag:Mg (94:3:3) NCs ratio, owing to the synergistic effect of the ion-releasing ability of Cu2+, Ag2+, and Mg2+ ions. It possesses a distinctive high aspect ratio shape, is ion-releasing, and has excellent cytocompatibility. The suitability of the Cu:Ag:Mg (94:3:3) NCs ratio for addressing microbial challenges in healthcare is suggested by their distinct characteristics, indicating the promising potential for future biomedical applications.

Polystyrene microplastics as carriers for nano-hydroxyapatite particles: Impact of surface functionalization and mechanistic insights

The potential of microplastics (MPs) to act as carriers for contaminants or engineered nanomaterials is of rising concern. However, directly determining the vector effect of polystyrene (PS) MPs towards nano-hydroxyapatite (nHAP) particles, a typical nano phosphorus fertilizer and soil remediation material, has been rarely studied. In this study, the interaction of differentially surface functionalized PS MPs with nHAP were investigated through batch experiments under different solution chemistry conditions. The results demonstrated that nHAP had the highest attachment/adsorption affinity onto carboxyl-functionalized PS, followed by bare PS and amino-functionalized PS under near-neutral pH conditions. Adsorption of nHAP exhibited a strong pH-dependent behavior with PS MPs, increasing under acidic-neutral pH (3−7) and decreasing at higher pH values. The presence of humic acid and NaCl hindered the adsorption of nHAP onto MPs. Scanning electron microscopy observations revealed a rod-like morphology for adsorbed nHAP, which was randomly distributed on MPs surface. Surface complexation and cation-π interaction were mainly responsible for the adsorption of nHAP as revealed by multiple spectroscopic analyses. These results provide mechanistic insights into nHAP-PS interactions and expound the effect of surface functionalization of PS on binding mechanisms, and thus bring important clues for better understanding the vector effects of MPs towards nanoparticles.

Preparation and Characterization of Durian Husk-Based Biocomposite Films Reinforced With Nanocellulose From Corn Husk and Pineapple Leaf.

This research explores the integration of corn husk nanocellulose (CHNc) and pineapple leaf nanocellulose (PLNc) as reinforcing agents in a carboxymethyl cellulose-based film derived from durian husk (CMCDH). Through a solvent-casting method, composite films were fabricated with varying nanocellulose contents (15, 30, and 45 wt%). Analysis using Fourier transform infrared spectroscopy and x-ray diffraction confirmed the effectiveness of alkaline and bleaching treatments in eliminating noncellulosic components. Transmission electron microscopy image revealed the rod-like morphology of CHNc and PLNc, with dimensions approximately 206.5 × 7.2 nm and 150.7 × 6.5 nm, respectively. The inclusion of nanocellulose decreased the transparency of CMCDH films while enhancing their tensile strength, thermal stability, and water vapor transmission rate. Notably, CMCDH/PLNc(30%) exhibited the highest tensile strength at 5.06 ± 0.83 MPa, representing a remarkable 220% increase compared to CMCDH biofilm. Thermogravimetric analysis and differential scanning calorimeter results indicated that nanocellulose incorporation delayed the film's decomposition temperature by approximately 10°C. Moreover, CMCDH/PLNc(30%) demonstrated the lowest water vapor transmission rate, marking a 20% improvement. However, the film's properties were compromised at the highest nanocellulose content (45 wt%) due to observed fiber aggregation, as revealed by scanning electron microscopy analysis.

Elucidating uniaxial negative thermal expansion and reversible phase transition in β-AgVO3 microrods: In situ PXRD and Raman scattering studies

This study investigates the thermal behavior and structural transitions of silver vanadate microrods (AgVO3) synthesized via coprecipitation. The samples were characterized at room temperature using scanning electron microscopy, Powder X-ray Diffraction, and Raman scattering. The AgVO3 was obtained in the monoclinic phase (β-phase) with a Cm space group and rod-like morphology of micrometer-sized diameter. In situ temperature-dependent studies utilizing XRD and Raman spectroscopy revealed notable findings: at low temperatures (298–12 K), the β-AgVO3 phase exhibited thermal stability alongside uniaxial negative thermal expansion (NTE) along the b lattice parameter of microcrystals. Conversely, experiments at high temperatures (298–673 K) demonstrated a reversible structural transition from the monoclinic phase to a triclinic phase at 473 K (β → β’), with NTE observed along the b direction in both high-temperature phases. These temperature-induced structural modifications and the observed uniaxial negative thermal expansion in β-AgVO3 microrods constitute significant contributions to the field, providing valuable insights into their thermal behavior and potential applications.

Amplification of intense red emission through integrating Li+ ions to V2O5:Eu3+ phosphors: Optical thermometry, cheiloscopy and extraction of level III features for individual identification

This study presents the synthesis of V2O5:Eu3+ phosphors in concentrations ranging from 1 to 9 mol %, using a solution combustion method with Areca Nut (A.N) as a bio-fuel. The samples exhibit an orthorhombic crystal structure, confirmed by powder X-ray diffraction (PXRD), and rod-like morphology as shown by field emission scanning electron microscopy (FE-SEM). Photoluminescence (PL) studies reveal that the emission intensity of the 5D0→7F2 transition at 619 nm increases with the Eu3+ concentration up to 5 mol %, where it peaks before quenching due to quadruple-quadruple interactions, according to the Van Uitert relation. To improve luminescence, Li+ ions are added, with the V2O5:5Eu3+ co-doped with 4Li+ (V2O5:5Eu3+, 4Li+) ions showing the highest PL intensity, about 5.03 times higher than that of Eu3+ alone. This optimized phosphor has Commission Internationale de l’Eclairage (CIE) chromaticity coordinates of (0.6022, 0.3963), closely matching commercial red-emitting phosphors and demonstrating a colour purity (CP) of 88.69 %. Thermal stability assessments indicate that these phosphors have a high activation energy (Ea) of about 0.224 eV, signifying robust thermal properties. The optimized V2O5:5Eu3+, 4Li+ phosphors efficiently reveal level I–III features in latent fingerprints (LFPs) and accurately identify lip prints (LPs) groove patterns of type I–VI under 365 nm UV light, providing high resolution and contrast. These characteristics make the optimized phosphor an excellent candidate for use in photonic devices, advanced forensic and data security applications.

Biogenically Synthesized ZnO and Cu-Doped ZnO Nanoparticles: Effect of Cu-Dopent Concentration and Annealing on Morphology and Optical Properties

In this work, ZnO nanoparticles and Cu-doped ZnO nanoparticles were biogenically synthesized using precipitation method in <i>Cissus quadrangularis</i> plant extract medium. The influence of Cu dopant on the crystalline structure, optical properties, and morphology of ZnO was investigated. The samples were characterized by XRD, FTIR, UV–vis spectroscopy and SEM. XRD patterns confirmed the wurtzite formation of doped and undoped ZnO nanoparticles. The average crystallite size of the neat and Cu-doped samples was ~18 nm irrespective of the amount of dopant. The annealing process enhanced the size of both the neat and Cu-doped samples. However, the influence on the size is less prominent in the Cu-doped sample than in the neat sample. The UV-visible spectral analysis shows that all the synthesized doped and undoped nano zinc oxides absorb at ~400nm. The band gap energy of Cu-doped ZnO particles was greater for unannealed samples whereas it was appreciably lowered on annealing for Cu-doped samples. SEM analysis shows rod-like morphology for the unannealed and annealed undoped zinc oxides. It is changed to flower-like morphology with the addition of 5mM Cu<sup>2+</sup> and then to nano sheet-like structure with the incorporation of higher amount of Cu<sup>2+</sup> ions. Annealing of zinc oxide samples leads to the smoothening of the surfaces with a change in morphology for the ZnO nanoparticles.

A novel high-entropy rare-earth hydroxycarbonate synthesized via facile hydrothermal synthesis with superior decomposition temperature

This study presents for the first time the synthesis of a novel high-entropy rare-earth hydroxycarbonate, specifically (Sm₀.₂La₀.₂Y₀.₂Nd₀.₂Gd₀.₂)(CO3)OH, by using a simple hydrothermal treatment. The resulting rare-earth hydroxycarbonate exhibits superior thermal stability compared to the related single-component rare-earth hydroxycarbonates, and a distinctive rod-like morphology, maintained even after prolonged calcination (i.e. 800 °C for 12 h), suggesting its potential as a “sacrificial template” for high-entropy bixbyite-structured oxides. Thus, our pioneering work opens new possibilities for the application of a novel class of high-entropy hydroxycarbonates in the field of catalysis, luminescence, and sensing technologies.

Turning black soldier fly rearing by-products into valuable materials: Valorisation through chitin and chitin nanocrystals production

The industry of insect-based proteins as feed and food products has been encountering a huge development since the last decade, and industrial-scale factories are now arising worldwide. Among all the species studied, Black Soldier Fly is one of the most promising and farmed. This rearing activity generates several by-products in the form of chitin-rich biomass that can be valorised to keep a virtuous production cycle embedded in the scope of the bioeconomy. Herein, we report the isolation of chitin and, for the first time, chitin nanocrystals (ChNCs) from all the BSF rearing by-products, i.e., moults (larval exuviae, puparium) and dead adults. Extraction yields, were dependent on the type of by-products and ranged from 5.8 % to 20.0 %, and the chemical structure of the extracts exhibited typical features of α-chitin, confirmed by FTIR, NMR, XRD and TGA analysis. Both STEM in SEM and AFM analysis confirmed the isolation of chitin nanocrystals presenting a rod-like morphology. The average nanocrystal height estimated by AFM ranged from 13 to 27 nm depending on the by-product sample. The following results highlighted the potential of BSF rearing by-products, promoting an approach to valorise those industrial waste and paving the way towards insect-based biorefinery.

Highly efficient Rh-doped MnO2 nanocatalysts for complete elimination of CO at room temperature.

Obliteration of carbon monoxide is significant due to its hazardous effect on human health and potential application in different fields. Catalytic CO oxidation at lower temperature is the most convenient method to diminish the toxicity of CO. The low-cost catalysts which are exhibiting higher activity at lower temperature with good stability are in demand. The nanosized Rh-doped MnO2 catalysts have been prepared by dextrose-assisted co-precipitation method. Catalytic CO oxidation reaction was carried out over these prepared nanocatalysts under environmentally suitable conditions. XRD confirms the phase formation of prepared catalysts. These samples exhibit rod-like morphology with thickness of rods of less than 10nm which is substantiated from electron microscopy images. XPS data reveals the oxidation state of Mn (+ 4) and Rh (+ 3). These catalysts are highly active for CO oxidation reaction at lower temperature, and one showed complete CO conversion at room temperature. The time-on-stream studies revealed that these catalysts are highly stable for CO oxidation for several hours. These catalysts are decidedly stable in moist condition and also showed higher activity in the presence of moisture, indicating participation of moisture in the oxidation reaction at above room temperatures.

Flexible Mesopores in Nanoscrolls: Extraordinarily Large Alteration of Pore Sizes and Their Reversibility.

Flexible porous materials have gained considerable interest for their potential applications in selective absorption and controlled release/storage of specific molecules or compounds. Here, nanoscrolls are proposed as a type of inorganic solids with reversibly flexible mesopores. Nanoscrolls exhibit a rolled-up structure composed of nanosheets with a 1D rod-like morphology, possessing two distinct nanospaces. The first space comprises 1D tubular mesopores located at the center of the rod, while the second space exists in the interlayer regions on the wall of the mesopore, resulting from the layer stacking caused by the scrolling of nanosheets. By replacing the interlayer cations on the nanoscroll walls with other cations, a drastic alteration in the size of the 1D mesopores is observed. For instance, exchanging bulky dodecylammonium cations with small NH4 + cations leads to a substantial change in pore size, with differences ranging from 10 to 20nm-a notably larger variation compared to previous reports on flexible porous materials. Importantly, the alteration of pore size induced by the exchange reaction is found to be reversible. This reversible alteration in pore size holds promise for applications in host-guest chemistry involving large moieties such as nanoparticles and enzymes.

Investigation of flame-retardant characteristics of natural flax coated with hydrothermally synthesized calcium borate and organic PDA

Flame-retardant behavior of flax fabric coated by calcium borate powders with clove-like and elongated morphologies was investigated by thermal analysis and cone calorimeter. PDA was used to form strong and uniform adhesion of calcium borate onto fabric. Thermal analysis showed a 20% of decrease in mass loss, while detected exothermic/endothermic peaks as a result of the degradation of fabric and PDA. Significant reductions in HRR, p-HRR, EHC and CO2 amount were observed for fabric coated by PDA and elongated calcium borate powder. PDA was carbonized at low temperatures and formed a char layer that prevented flame propagation. At the same time, calcium borate powder dilutes the flammable gases in the environment with the release of water within its body. Among the calcium borate powders, rod-like morphology showed the best flame-retardant performance.

Diaminonaphthalene functionalized LUS-1 as a fluorescence probe for simultaneous detection of Hg2+ and Fe3+ in Vetiver grass and Spinach

One of the important problems in the environment is heavy metal pollution, and fluorescence is one of the best methods for their detection due to its sensitivity, selectivity, and relatively rapid and easy operation. In this study, 1,8-diaminonaphthalene functionalized super-stable mesoporous silica (DAN-LUS-1) was synthesized and used as a fluorescence probe to identify Hg2+ and Fe3+ in food samples. The TGA and FT-IR spectra illustrated that 1,8-diaminonaphthalene was grafted into LUS-1. XRD patterns verified that the LUS-1 and functionalized mesoporous silica have a hexagonal symmetrical array of nano-channels. SEM images showed that the rod-like morphology of LUS-1 was preserved in DAN-LUS-1. Also, surface area and pore diameter decreased from 824 m2 g⁻1 and 3.61 nm for the pure LUS-1 to 748 m2 g⁻1 and 3.43 nm for the DAN-LUS-1, as determined by N₂ adsorption–desorption isotherms. This reduction demonstrated that 1,8-diaminonaphthalene immobilized into the pore of LUS-1. The DAN-LUS-1 fluorescence properties as a chemical sensor were studied with a 340/407 nm excitation/emission wavelength that was quenched by Hg2+ and Fe3+ ions. Hg2+ and Fe3+ were quantified using the fluorescence response in the working range 8.25–13.79 × 10–6 and 3.84–10.71 × 10–6 mol/L, with detection limits of 8.5 × 10–8 M and 1.3 × 10–7 M, respectively. Hg2+ and Fe3+ were measured in vetiver grass and spinach. Since the Fe3+ quenching can move in the opposite direction with sodium hexametaphosphate (SHMP) as a hiding compound for Fe3+, consequently, the circuit logic system was established with Fe3+, Hg2+, and SHMP as inputs and the fluorescent quench as the output.