Number Of Bilayers Research Articles

Optimization Design of Pt/C Multilayer Supermirrorsfor Hard X-rays

Aperiodic multilayers have important applications in hard X-rays astronomical observations due to their broadband responses. This paper presents an optimization model of Pt/C power-law graded stack multilayers using the IMD software. The reflectivity expression of multilayers was derived from the reflection theory of X-ray multilayers and Fresnel recursion formulas. Then, the effects of maximum bi-layer thickness ([Formula: see text]), ratio of high-density material thickness to bi-layer thickness ([Formula: see text]), power-law index ([Formula: see text]), number of bi-layers ([Formula: see text]), grazing incidence angle ([Formula: see text]), interfacial roughness ([Formula: see text]), and photon energy ([Formula: see text]) on the reflectivity were analyzed. The calculation results showed that the [Formula: see text], [Formula: see text] and [Formula: see text] control the shift of response range, absorption peak and Bragg peaks, respectively. And the decrease of [Formula: see text] and increase of [Formula: see text] and [Formula: see text] can result in the reduction of reflectivity at different energies. Additionally, an optimized multilayer structure was proposed according to the extremum of merit function, which can achieve a broadband reflectivity of no less than 0.6 from 1[Formula: see text]keV up to 80[Formula: see text]keV. These results can provide important references for the response characteristic analysis and optimization design of multilayers.

HfO2/Al2O3 Multilayer on Parabolic Cylinder Substrate to Monochromatize and Collimate Divergent X-Ray Beam

A monochromatic parallel X-ray beam is essential for some X-ray applications and a multilayer on a parabolic cylinder substrate is a good choice to obtain it. In this work, an HfO2/Al2O3 multilayer with a period of 3.80 nm and a bilayer number of 60 is grown on a smooth, flat Si substrate via atomic layer deposition for a monochromatizing Cu kα 0.154 nm X-ray and the first-order peak of the X-ray reflectivity is about 45%. The multilayer-coated Si substrate is then glued on a pre-made stainless steel body with a designed parabolic cylinder profile to convert divergent X-rays from a laboratory X-ray source into a parallel beam. The surface profiles before and after gluing Si on the stainless steel body are almost the same and basically consistent with the designed one. The results show that a monochromatic parallel X-ray (0.154 nm) beam can be acquired by an HfO2/Al2O3 multilayer on a parabolic cylinder substrate and the divergence angle of the reflected beam is 0.67 mrad.

Using Layer-by-layer Assembled Clay Composite Junctions to Enhance the Water Dissociation in Bipolar Membranes.

Bipolar membranes (BPMs) with a layer-by-layer (LbL) assembled montmorillonite (K30 MMT) clay-polyelectrolyte (PE) composite junction coated onto a sulfonated poly(ether ether ketone (SPEEK)) electrospun support are prepared, characterized and their water dissociation performance is analyzed. In particular, the focus is on the effect of the presence of the K30 MMT clay as a catalyst for water dissociation, the bilayer number (three, six, and nine), and the PE strength (poly(ethylenimine) (PEI) as a weak PE and poly(diallyl dimethylammonium chloride) (PDADMAC) as a strong PE) on the BPM performance. The BPMs are prepared by electrospinning and hot pressing SPEEK and the Fumion FAA-3 polymer. Adding the composite multilayers in the BPM junction decreases the membrane area resistance in reverse bias from 560 to 21 Ohms cm2 for the best-performing modified BPM. The bilayer number has limited influence on the overall membrane resistance, while the PDADMAC BPMs outperform the PEI BPMs due to the higher and more stable PE and clay adsorptions. Electrochemical impedance spectroscopy shows that the depletion layer thickness decreases exponentially with the number of bilayers as the water dissociation reaction becomes less dependent on the junction electric field. Furthermore, the higher Donnan exclusion at the modified junctions improves the BPM permselectivity 3-fold compared to the BPM containing no catalyst. Altogether, these improvements lead to 6.7 times less energy being used in BPM electrodialysis for the production of acid and base when a BPM with composite LBL junction is used compared to a BPM without catalyst. Thus, adding MMT clay composite LbL catalyst to BPM junctions is a promising method to improve the efficiency and reduce the energy consumption of electrochemical processes that rely on BPMs.

Synergistic Effect of Surface Hydrophobicity and <i>In-Vitro</i> Antimicrobial Activity of Polymeric Nano-Formulation in Textile Finishing

Fouling and damage of variety of surfaces including textile material is a global challenge. As textile wears next to the skin and health issues are more significant. Thus in an effort to address the issues related to textile surfaces damage, antimicrobial polymeric textile finishing was developed to impart antimicrobial functionalities to the textile fabric. The nanoprecipitation technique was done to synthesize antimicrobial polymeric nanoparticles and applied on to the cotton textile fabric via layer-by-layer self-assembled multilayers dip coating technique. The particle size and zeta potential of the nanoparticles was evaluated form dynamic light scattering analysis (DLS) as 216 nm and-11.2 mV. The antimicrobial polymeric finishing of cotton textile was done by alternate dip coating in polyelectrolytes and nanoformulation. The structural morphology and roughness of the resultant textile was studied by SEM and optical profilometery. While the surface hydrophobicity was found to increase with the number of bilayers coating of hydrophobic polymeric formulation as measured in term of contact angle θ. In-vitro antimicrobial activity was studied against gram negative E. coli and gram positive S. aureus with significant zone of inhibition against both strains. Thus surface hydrophobicity and antimicrobial activity of the textile fabric was synergistically achieved and have potential for biomedical and industrial application.

Liposomes – metabolically active drug transport systems: classification, components, preparation methods, and stabilization. Part 1 (review)

Introduction. This review article is focused on the modern classification of liposomes, preparation methods, stabilization and the role of structural components, visualization, and pharmacokinetics. Part 1 discusses the first three aspects mentioned above.Text. Depending on the size and number of bilayers, liposomes are classified into simple, long-circulating, cationic, immuno-liposomes, and sterically stabilized. The lipid components of liposomes can have a pronounced effect on target organs and tissues. Metabolites of the main components of liposomes have their biological activity, depending on their combination and dosage. All of the above indicates the promise of using liposomes not only as carriers of drugs but also as independent effectors that can have a significant impact on human metabolism in various diseases. The advantages and limitations of methods for preparing liposomes, and the features for manufacturing stealth liposomes are discussed. A special section of the article is dedicated to liposome stabilization.Conclusions. The information discussed in the review article may be useful in the development of pharmaceutical formulations in liposomes. Liposomes are not only promising nanocontainers for targeted drug delivery, but also metabolically active complexes with a wide spectrum of activity.

Effect of inserting a-C layers on anticorrosion behavior of Ni-NiCr-NiCrAlSi composite coating on copper through magnetron sputtering for marine applications

Amorphous carbon film by magnetron sputtering was inserted in the NiCrAlSi layer to form NiCrAlSi/a-C multilayer with modulation period in a range of 131.6 nm to 240.2 nm in the Ni-NiCr-NiCrAlSi coating for a further improvement to copper on corrosion resistance aiming at application as a heat exchanger for mariculture in sea water. After structure characterization, the corrosion behavior of the samples with variant modulation periods of the NiCrAlSi/a-C multilayer keeping the same total thickness(1 μm) was compared using potentiodynamic polarization and electrochemical impedance spectroscopy. The polarization curves show that the corrosion potentials of the coatings with modulation periods of 240.2 nm, 198.4 nm, 158.4 nm and bilayer number 4, 5, 6 for NiCrAlSi/a-C layer are more negative compared to that with modulation period of 131.6 nm and bilayer number 7, which indicates that the smallest modulation period results in the highest corrosion resistance. The amorphous a-C sublayer in the multilayer coatings plays an active role in the improvement, for an introduction of the more interfaces between the NiCrAlSi and the a-C sublayers, as well as the compact structure and the chemical inertness to sea water (Cl−). In addition, the NiCrAlSi sublayer can be regarded as an interlayer to release stress in both the a-C sublayer and the NiCrAlSi sublayer, mainly from corrosion products, which also plays an important role for the improved corrosion resistance.

Evolution of interface and surface morphology of WC/SiC multilayers with increase in number of bilayers

WC/SiC multilayer mirrors are promising elements for operation in the short wavelength range of hard X-rays and even gamma-rays. A set of WC/SiC multilayers with nominal bilayer thickness of 3.0 nm with 30, 50, 100, and 200 bilayers have been deposited by magnetron sputtering method. The evolution of interface and surface morphology with addition of the number of bilayers has been investigated. The methods of grazing incidence X-ray reflectivity, X-ray diffuse scattering, optical profiler, atomic force microscope, transmission electron microscopy and energy-dispersive X-ray spectroscopy have been used. It is found that the interface roughness plays a dominant role in interface imperfections of WC/SiC and it exhibits slight accumulation across the multilayers with the number of bilayers increasing. The surface roughness also increases in relatively high spatial frequency range as the number of bilayers has been added, due to the cumulative increase in interface roughness. The interface roughness accumulation ultimately contributes to the diminishment of optical performance of WC/SiC multilayers with a large number of bilayers. At the wavelength of 0.154 nm, a peak reflectivity of 69.2 % is achieved for a 100 bi-layer multilayer under the grazing incidence of approximately 1.5°, while lower reflectivity of 67.2 % for a 200 bi-layer multilayer.

Optimizing transparent electrodes: Interplay of high purity SWCNTs network and a polymer

The discovery of transparent electrodes led to the development of optoelectronic devices such as touchscreens, infrared (IR) sensors, etc. Carbon nanotubes (CNTs) have been a potential replacement for ITO due to their exceptional properties, especially in the IR region. In this work, we present the development of a CNT-polymer composite thin film that exhibits outstanding transparency across visible and IR spectra prepared by layer-by-layer (LbL) technique. This approach ensures uniform integration and crosslinking of CNTs into lightweight matrices, and also represents a cost-effective method for producing transparent electrodes with remarkable properties. The produced films achieved a transparency above 80 % in the UV/VIS range and approximately 70 % in the mid-IR range. The sheet resistance of the fabricated thin films was measured at about 4 kΩ/sq, showing a tendency to decrease with the number of bilayers. In this work we have investigated electrical properties and transport mechanisms in more detail with computational analysis. Computational analysis was performed to better understand the electrical behavior of nanotube-polymer junctions in the interbundle structure. Based on all results, we propose that the transparent electrodes with 4 and 6 bilayers are the most optimal structures in terms of optical and electrical properties.

Ultrathin Polyelectrolyte Multilayer Films with Silver Nanoparticles as a Potential Antibacterial Coating

Silv er nanoparticles (AgNPs) are already used as antibacterial agents for medical devices and food packaging materials. However, concerns about its toxicity still exist. AgNPs can be incorporated into ultrathin polyelectrolyte multilayer (PEM) films to minimize this risk. With PEMs, full surface coverage can be achieved with minimal AgNPs, minimizing human exposure. In this study, a simple protocol to fabricate ultrathin PEM/AgNP films using sodium ascorbate as a reductant was developed. The effects of the number of bilayers and ionic strength (0.05 to 0.50 M) on film thickness and amount of AgNPs were investigated. UV/VIS spectra show that increasing the number of bilayers from 1 to 5 would lead to a corresponding increase in film thickness and amount of synthesized AgNPs. Thicker layers and more AgNPs were deposited when the films were fabricated under higher ionic strengths. Films with thicknesses ranging from 15.67 to 87.13 nm were fabricated. The sizes of the incorporated AgNPs were between 54.32 and 259.26 nm, as characterized by scanning electron microscopy. All films were stable when submerged in water for 240 h, suggesting the migration of Ag/Ag+ from the films was minimal. The antibacterial efficacy of the films against Staphylococcus aureus was also assessed. Only the PEM/AgNP films fabricated with the highest salt concentration (0.50 M) showed antibacterial activity under resazurin assay. However, the Kirby Bauer method showed inhibition zones for all films fabricated under all salt concentrations, indicating antibacterial activity at the interface of the bacterial lawn and the films, even with the slow migration of Ag/Ag+. Thus, PEM/AgNP films have the potential to be used as an antibacterial coating.

Ion-Mediated Structural Discontinuities in Phospholipid Vesicles.

Despite intense research, methods for controlling soft matter's spontaneous self-assembly into well-defined layers remain a significant challenge. We observed ion-induced structural discontinuities of phospholipid vesicles that can be exploited for controlled self-assembly of soft materials, using DOPC and NaCl as a model system. The observations were made for the 0.25 wt % lipid concentration. We used dynamic light scattering, zeta-potential measurement, cryo-electron microscopy, small-angle X-ray, and small-angle neutron scattering to understand the reason for the discontinuities. For salt concentrations below 8 mM, we observed a decrease in the liposome diameter with increased NaCl concentration. Above 8 mM, we measured a discontinuity; the radius increases within a very narrow salt concentration range within less than 0.1 mM and then decreases for values greater than 8 mM. At 75 mM, the radius becomes constant until it grows again at around 500 mM. Microscopy and scattering experiments show a transition from unilamellar to bilamellar at 8 mM and to trilamellar at 75 mM. At 500 mM, we found a heterogeneous liposome system with many different bilayer numbers. All the experimental observations indicate that declining solvent quality and increasing osmotic pressure direct lipids to expel preferentially to the inner compartment. Upon reaching a critical concentration, excess lipids can form a new bilayer. This spontaneous self-assembly process causes simultaneous shrinkage of the aqueous core and expansion of the vesicle. This approach opens an intriguing path for controlling the self-assembly of bioinspired colloids.

Magnetic properties and magnetoresistance of hybrid multilayer nanostructures {[(Co40Fe40B20)34(SiO2)66]/[ZnO]}n

The structural, electrical, magnetic, magneto-optical properties and magnetoresistance of {[(Co40Fe40B20)34(SiO2)66]/[ZnO]}n multilayer structures, where n = 50 is the number of bilayers (Co40Fe40B20)34(SiO2)66 nanocomposite and ZnO have been studied. The thicknesses of (Co40Fe40B20)34(SiO2)66 nanocomposite layers as well as ZnO spacers were varied in a wide range. The samples were synthesized by ion-beam sputtering onto glass ceramic substrates. The (Co40Fe40B20)34(SiO2)66 composite have an amorphous structure and the semiconductor ZnO interlayers have a hexagonal crystalline structure with the p63mc symmetry group. The nanocomposite layers containing a ferromagnetic component far from the percolation threshold are in a superparamagnetic state. The presented in the paper data of magnetization, magneto-optical transverse Kerr effect and magnetoresistance indicates that long-range ferromagnetic order does not form down to 77 K both for references ZnO films and studied multilayers with thin and thick ZnO interlayers. An increase in the magneto-optical signal in multilayers compared to references (Co40Fe40B20)34(SiO2)66 composite films has been detected at 1.2 eV. The magnetoresistance of {[(Co40Fe40B20)34(SiO2)66]/[ZnO]}n multilayers with thick (>32 nm) ZnO interlayers is lower than in reference (Co40Fe40B20)34(SiO2)66 nanocomposite, while at thin ZnO interlayers magnetoresistance is significantly higher and reaches 12 % at temperatures of 77 К. Possible mechanisms of ferromagnetic and antiferromagnetic ordering, enhancement of the magneto-optical response and magnetoresistance in {[(Co40Fe40B20)34(SiO2)66]/[ZnO]}n multilayer nanostructures are discussed.

Strongly coupled quasi bound states in the continuum stimulated by Bloch surface wave in the non-subwavelength metamaterials

Bound states in the continuum (BICs) are unique in their ability to maintain high quality factor (Q factor) within non-Hermitian platforms that have open scattering channels. Simultaneously, Bloch surface waves (BSWs), guided modes with photonic bands positioned below the light line, confine optical energy on device surfaces. Although BICs and BSWs are generally located on opposite sides of the light line without intersecting, we put forward a novel concept that these two phenomena could be interconnected through a non-subwavelength structure. Specifically, BSWs in a graphene metamaterial can stimulate a strongly coupled quasi-BIC by mode coupling, reminiscent of the Friedrich-Wintgen BIC (FW BIC) that has sparked our interest. We delve into the intricate generation mechanism of this coupled quasi-BIC, uncovering that within metamaterials comprising two-dimensional (2D) grating structures, BSWs remarkably enhance the Q factor of few-diffraction-order (FDO) resonances. Another intriguing discovery is that altering the number of bilayers allows the coupled quasi-BIC to manifest after the photonic bands go over an exceptional point. Advancing further, we expand the 2D grating concept to a 3D square block structure, demonstrating that the coupled quasi-BIC associated with the BIC of 0th-order diffraction, can substantially improve the Q factor. The insights gained from these manipulations have practical implications for high-Q metadevices, paving the way for BIC-based sensor, filter, and absorber research.

Enhanced Spontaneous Emission through High‐k Modes in CsPbBr3 Perovskite Hyperbolic Metamaterials

AbstractNovel optical sources require fast decay rates, making hyperbolic metamaterials (HMMs) an increasingly attractive option. HMMs are well‐known for their remarkable anisotropy, and leverage hyperbolic dispersion to enhance the decay rate of a fluorophore placed on top of them. This study tackles the complex task of embedding a fluorophore into an HMM, successfully overcoming challenges related to surface roughness, thickness imperfections, and layer washing effects. Specifically, CsPbBr3 perovskite nanocrystals (NCs)‐based HMM are fabricated, by alternating silver/nanocrystals (Ag/NCs) layers. Through a systematic investigation of the photophysical response following the deposition of each bilayer, compelling evidence of the achievement of hyperbolic dispersion is provided. Specifically, the impact of “high‐k” modes is isolated, which is distinctive to the HMM architecture. Therefore, the longstanding debate regarding the number of bilayers needed to achieve hyperbolic dispersion is conclusively resolved. The research demonstrates a nearly twofold increase in the decay rate and a threefold enhancement in photoluminescence intensity. These findings are further supported by theoretical Purcell factor calculations. This study marks a pioneering advancement in the field of bulk dye‐embedded HMMs, laying the groundwork for the development of advanced optical sources such as “resonant gain HMMs”.

Preparation of polycyclosiloxane/ZnO nanoparticle hybrid ultrathin films by Layer-by-Layer assembly methods

Layer-by-layer (LbL) assembly methods through alternative dipping processes were used to prepare hybrid nanoassemblies of 5 nm ZnO nanoparticles (ZnONPs) with catechol-functionalized polycyclosiloxane (CFPS60, 51.9 mol% catechol content). ZnONPs were assembled on solid substrates regularly and firmly through interactions with 4 nm-thick CFPS60, proved using UV-vis absorption measurements, atomic force microscopy and peel-off test. ZnONPs exhibited yellow photoluminescence (PL) in CFPS60/ZnONPs films, and the PL intensity increased notably as the number of bilayers increased. The work demonstrates that CFPS60 has a good hybrid nanoassembly formation capability, which is promising for next-generation optoelectronic device applications.

Skew scattering dominated anomalous Hall effect in Si/Ni multilayers containing varying number of bilayers

A systematic study of the skew scattering dominated anomalous Hall effect (AHE) in Si/Ni multilayers has been carried out on several samples containing different number of bilayers. The investigation is performed by preparing a series of Si10Å/Ni30ÅN multilayers. When the number of bilayers (N) is decreased, structural analysis showed that the size of Ni nanocrystallites and the distance between them decreases whereas their count rises. As a result, the saturation magnetization lowers with N. Furthermore, the perpendicular magnetic anisotropy of the multilayers improves as N is reduced. The saturated AHE resistance (RHSA) is also found to decrease as N increases due to the decreases of the Si/Ni interface area and scattering effect from the Ni nanocrystallites. A maximum of about 28 times enhancement in RHSA is observed for the sample with N = 1 when compared with that for N = 24. It is seen that the skew scattering is the dominant mechanism which is responsible for the AHE in the Si/Ni multilayers.

Biodegradable Local Chemotherapy Platform with Prolonged and Controlled Release of Doxorubicin for the Prevention of Local Tumor Recurrence.

Local recurrence after surgical and therapeutic treatment remains a significant clinical problem in oncology. Recurrence may be due to imperfections in existing therapies, particularly chemotherapy. To improve antitumor activity and prevent local cancer recurrence while keeping toxicity at acceptable levels, we have developed and demonstrated a biodegradable local chemotherapy platform that provides controlled and prolonged drug release. The platform consists of a polycaprolactone (PCL) substrate, which provides the structural integrity of the platform and the predominant unidirectional drug release, and a thin multilayer coating (∼200 nm) containing doxorubicin (DOX). The coating is an electrostatic complex obtained by the layer-by-layer (LbL) assembly and consists of natural polyelectrolytes [poly-γ-glutamic acid (γ-PGA) and chitosan (CS) or poly-l-lysine (PLL)]. To improve the release stability, an ionic conjugate of DOX and γ-PGA was prepared and incorporated into the multilayer coating. By varying the structure of the coating by adding empty (without DOX) bilayers, we were able to control the kinetics of drug release. The resulting platforms contained equal numbers of empty bilayers and DOX-loaded bilayers (15 + 15 or 30 + 30 bilayers) with a maximum loading of 566 ng/cm2. The platforms demonstrated prolonged and fairly uniform drug release for more than 5 months while retaining antitumor activity in vitro on ovarian cancer cells (SKOV-3). The empty platforms (without DOX) showed good cytocompatibility and no cytotoxicity to human fibroblasts and SKOV-3 cells. This study presents the development of a local chemotherapy platform consisting of a PCL-based substrate which provides structural stability and a biodegradable polyelectrolyte layered coating which combines layers containing a polyanion ionic complex with DOX with empty bilayers to ensure prolonged and controlled drug release. Our results may provide a basis for improving the efficacy of chemotherapy using drug delivery systems.

Bio-inspired transparent and antibiofouling diamond films via layer-by-layer self-assembly seeding

Bio-inspired diamond nanostructures featuring high transparency and anti-bacterial adhesion were constructed via layer-by-layer (LbL) self-assembly seeding and chemical vapor deposition growth. The topography of the diamond nanofilms was determined by initial nanodiamond seeds distribution, which was adjusted by nanodiamond colloidal stability. With increasing number of LbL bilayers, the bulge size and roughness of the deposited films increased. With increasing number of bilayers from 1 to 5, UV–Vis transmittance slightly decreased from max. 90 %–83 %, while the contact angle increased from 90° to 130°. All the nanostructured diamond films possess very high IR transmittance between 85% and 90%, which is close to the bare quartz (95%). Compared with conventional flat diamond films, nanostructured diamond films repelled most of the bacteria, suggesting excellent anti-biofouling property. With increasing seeding bilayer number, more bacteria were repelled. The highest bacterial reduction was achieved to 99% by diamond film seeded with 5 bilayers. The bio-mimicking nanostructured diamond film represent a potent solution for achieving highly transparent, anti-biofouling and highly durable optical coatings for biomedical and marine optical instrument.

Effects of multilayer structure on impacting fatigue resistance and high-speed dry cutting performance against Ti-6Al-4 V of AlTiN/AlTiBN multilayer coatings

AlTiN/AlTiBN multilayer coatings with various numbers of bilayers were constructed to evaluate their high-frequency cyclic impact resistances and high-speed dry cutting performances. The multilayer coatings showed improvement in adhesion, micro-hardness as well as resistance to impacting fatigue and thermal decomposition. High-speed dry cutting (80 and 100 m/min without cutting fluid) experiments manifested the enhanced resistance to crack generation, delamination and rapid failure of coated tools by construction of multilayer structure, and the C5 coated tool presented better cutting lifetime of ∼2800 m (80 m/min) and ∼1200 m (100 m/min) ascribed to the best adhesive strength of 96 N (Lc2), the highest hot-hardness (3375 HK0.025 at 1000 °C) as well as the best fatigue resistance.

Durable silver nanowire transparent electrodes enabled by biorenewable nanocoating using chitin and cellulose nanofibers for flexible electronics.

The protection of silver nanowire (AgNW) networks is crucial for enhancing their durability and applicability to flexible electronics. In this study, we present a sustainable and efficient strategy to protect AgNW-based flexible transparent electrodes (FTEs) using a layer-by-layer (LBL) assembly of biorenewable chitin and cellulose nanofibers (Chi and Cell). These uniform LBL-assembled thin films were successfully fabricated on AgNW FTEs due to their opposite surface charges. The resulting (Chi/Cell)n bilayers, where n is the number of bilayers, did not degrade the optoelectrical properties of AgNW FTEs and significantly enhanced their stability under various harsh conditions. The optimized (Chi/Cell)10@Al-AgNW FTEs exhibited comprehensive stability against UV/O3 treatment for 40 min, thermal treatment at 250 °C for 350 min, Na2S (1%), HCl (10%), and NH3 (30%) treatments for 3, 30, and 105 min, respectively, sonication for 300 min, and 10 000 cycles of bending test. Therefore, the (Chi/Cell)10@Al-AgNW FTEs were successfully applied to transparent heaters (TH) and pressure sensors with remarkably improved applicability, durability, and performance compared to pristine AgNW FTEs, providing a reassuring solution to the stability issues of AgNW-based FTEs.

Coir based biofiltration system for enhanced removal of water pollutants

This study examines the use of layer by layer (LbL) coated coir (CC) systems to eliminate bacterial pathogens and emerging contaminants from water. Bacterial and chemical contaminants found in river water pose risks to human health and aquatic ecosystems. The study initially compared the effectiveness of CC to uncoated coir (UC) treatment in removing bacterial pathogens. CC treatment demonstrated superior removal efficacy compared to UC treatment. For samples with a bacterial concentration of 3.6×103 CFU/mL, CC treatment achieved a removal rate exceeding 90% and viability losses of over 60% for E. coli and over 90% for S. aureus. As the number of bilayers increased, the regrowth potential of bacteria decreased, leading to mortality rates of ∼ 97% for S. aureus and 65% for E. coli respectively. Furthermore, the superiority of CC over UC in removing emerging contaminants were demonstrated. CC attained removal efficiencies of over 99% for isoniazid, 95.08% for lidocaine, 95.21% for mefenamic acid, and 87.73% for caffeine. The reproducibility of the CC system was tested and showed stable removal efficiency over multiple cycles. These findings highlight the potential of CC systems as effective eco-friendly alternatives for water purification to remove bacterial pathogens and emerging contaminants.