Fabrication Of Substrates Research Articles

An UHF band planar resonator temperature sensor constructed from high-performance titanium dioxide system microwave dielectric ceramics: Toward integrated ceramic-based sensor devices

With the rapid fusion of temperature sensing technology and microwave technology, microwave temperature sensors have become the protagonist of competing research. We propose a planar resonator temperature sensor that combines substrate material modifications with sensor structure design. To realize this concept, high-performance TiO2-xwt. % ZnO (0 ≤ x ≤ 3) microwave dielectric ceramics are prepared. The various factors influencing dielectric properties, including crystal structure, phase composition, Raman vibration, microstructure, element valence, and oxygen vacancy, are completely investigated. The TiO2-0.7 wt. % ZnO ceramic exhibiting exceptional properties (εr = 106.6, Qf = 46 000 GHz, τf = 426.0 ppm/°C) is selected for substrate fabrication. The frequency and temperature dependence of εr and tan δ are analyzed at 2–4.5 GHz from −50 to 100 °C, revealing a good linearity between εr and temperature. A CSRR temperature sensor employing this substrate material is designed, simulated, fabricated, and validated from −50 to 90 °C. This sensor generates two resonance frequencies (around 0.5 and 1.4 GHz) in the UHF band, demonstrating sensitivities of 2.2 MHz/10 °C and 6.3 MHz/10 °C at the first and second resonance frequencies, along with an outstanding normalized sensitivity of approximately 0.045. Through a comprehensive analysis of the physical mechanisms affecting the sensor's sensitivity and quality factor, the design of the sensor is strengthened from the perspective of optimizing the performance of microwave dielectric ceramics. The regulation mechanism of dielectric characteristics is enriched and clarified, thereby achieving a synergistic improvement in sensor performance. This work expands the application scope of microwave dielectric ceramics and provides an innovative approach to environmental monitoring.

A multi-functional coating on cotton fabric to incorporate electro-conductive, anti-bacterial, and flame-retardant properties

Multi-functional textiles have become a growing trend among smart customers who dream of having multiple functionalities in a single product. Thus, this study aimed to develop a multi-functional textile from a common textile substrate like cotton equipped with electrically conductive, anti-bacterial, and flame-retardant properties. Herein, a bunch of compounds from various sources like petro-based poly-aniline (PANI), phosphoric acid (H3PO4), inorganic silver nanoparticles (Ag-NPs), and biomass-sourced fish scale protein (FSP) were used. The coating was prepared via in-situ polymerization of PANI with the cotton substrate, followed by the dipping in AGNPs solution, layer-by-layer deposition of FSP and sodium alginate, and finally, a dip-dry-cure technique after immersing the modified cotton substrate into the H3PO4 and citric acid solution. The key results indicated that the fabric treated with PANI/Ag-NPs/FSP/P-compound exhibited a balanced improvement in all three desired properties as the electrical resistance was reduced by 44.44 % while showing superior bacterial inhibition against gram-positive bacteria (S. aureus) and gram-negative bacteria (E. coli), and produced dense-black carbonaceous char residues, indicating its flame retardant properties as well. Thus, such amicable developments made the cotton textile substrate a multi-functional textile, which showed potential to be used in medical textiles, wearable electronics, fire-fighter suits, etc.

Self-Cooling Textiles—Substrate Independent Energy-Free Method Using Radiative Cooling Technology

Due to climate change, population increase, and the urban heat island effect (UHI), the demand for cooling energy, especially in urban areas, has increased and will further increase in the future. Technologies such as radiative cooling offer a sustainable and energy-free solution by using the wavelength ranges of the atmosphere that are transparent to electromagnetic radiation, the so-called atmospheric window (8–13 µm), to emit thermal radiation into the colder (3 K) outer space. Previous publications in the field of textile building cooling have focused on specific fiber structures and textile substrate materials as well as complex multi-layer constructions, which restrict the use for highly scaled outdoor applications. This paper describes the development of a novel substrate-independent coating with spectrally selective radiative properties. By adapting the coating parameters and combining low-emitting and solar-reflective particles, along with a matrix material emitting strongly in the mid-infrared range (MIR), substrate-independent cooling below ambient temperature is achieved. Moreover, the coating is designed to be easily applicable, with a low thickness, to ensure high flexibility and scalability, making it suitable for various applications such as membrane architecture, textile roofs, or tent construction. The results show a median daytime temperature reduction (7 a.m.–7 p.m.) of 2 °C below ambient temperature on a hot summer day.

An alternative chlorine-assisted optimization of CdS/Sb2Se3 solar cells: Towards understanding of chlorine incorporation mechanism

The current strategies in the development of Sb2Se3 thin film solar cells involve fabrication and optimization of superstrate and substrate device architectures, with the preferable choice for TiO2 and CdS heterojunction layers. For CdS-based superstrate cells, several studies reported the necessity to apply CdCl2 or other metal halide-based post-deposition treatment (PDT), highlighting improvement of CdS/Sb2Se3 device efficiency. However, the need, effect, and mechanism of such PDT are very often not described. Additionally, the fact that many groups have not succeeded in demonstrating its benefits suggests that this strategy is not straightforward, requiring a deeper understanding towards a more unified concept. The present study proposes an alternative approach to the challenging CdCl2 PDT of CdS in CdS/Sb2Se3 device, involving controllable Cl incorporation in CdS films by systematically varying the concentration of NH4Cl in the CBD precursor solution from 1 to 8 mM. Structural and electrical characterizations are correlated with advanced measurements of Scanning Kelvin Probe, surface photovoltage, and atomic force microscopy to understand the impact of Cl incorporation on the properties of CdS films and CdS/Sb2Se3 devices. The validity of Cl incorporation in the CdS lattice and interdiffusion processes at the CdS-Sb2Se3 interface is confirmed by secondary ion mass spectrometry analysis. It is demonstrated that incorporation of 1 mM of NH4Cl, as a Cl source in CBD CdS, can boost the PCE of CdS/Sb2Se3 by ∼20 %. With this approach, we offer new perspectives on the optimization methodology for Cl-based CdS/Sb2Se3 device processing and complementary understanding of the physiochemistry behind these processes.

Disposable Zirconium trisulfide-Reduced graphene oxide modified conducting thread based electrochemical biosensor for lung cancer diagnosis

Flexible technology in sensors have received much attention in monitoring of human health through various physiological indicators. Thus, it drawn a lot of interest in the development of flexible substrate for the diagnosis of various diseases via analysis of analytes. Present work focusses on the development of ecofriendly, portable, flexible, conducting thread (Th) and used as smart substrate for fabrication of biosensor towards ultrasensitive detection of the lung cancer biomarker (cytoskeleton-associated protein 4; CKAP4). The zirconium trisulfide-reduced graphene oxide nanocomposite and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) modified cotton thread based biosensor was fabricated via dip coating method. Next, successive immobilization of monoclonal antibodies of CKAP4 (anti-CKAP4) and bovine serum albumin (BSA) was performed via drop cast approach using fabricated electrode [nZrS3@rGO/PEDOT:PSS/Th]. The response of fabricated electrode (BSA/anti-CKAP4/ZrS3@rGO/PEDOT:PSS/Th) was recorded electrochemically versus CKAP4 concentration via chronoamperometry (CA). The results showed wider linear detection range of 6.25-800 pg mL−1, excellent sensitivity of 85.2 µA[log(pg mL−1)]-1cm−2 with good stability up to 42 days. The response of fabricated biosensor was supported by investigating response of CKAP4 biomarker present in patients of lung cancer (concentration as determined through enzyme-linked immunosorbent assay) and obtained results exhibited excellent correlation with that of standard samples.

Fabrication of compact substrate integrated waveguide dual band bandpass filter using complementary split-ring resonators for C and X band applications

This article presents a compact dual-band Bandpass Filter(BPF) based substrate integrated waveguide(SIW) used for C and X band applications. Complementary split-ring resonators(CSRR) are loaded into the waveguide surface to obtain more advantages of compactness and good performance. The SIW cavity undergoes initial optimization utilizing the powerful genetic algorithm, renowned for its robustness in solving complex problems, before proceeding to simulation with Ansys HFSS software with loaded CSRRs. The filter displays two passbands: the first has a bandwidth of 2 GHz and resonates at 6.8 GHz, while the second has a bandwidth of 5,55 GHz and resonates at 10.3 GHz. Moreover, with two resonance frequencies, the developed BPF has the benefit of low insertion loss(S21=-1.7dB and -1.9 dB) and improved return loss: (S11=-24dB and -22 dB) respectively. Furthermore, the proposed combination not only allows the implementation of a forward-wave passband propagating below the characteristic cutoff frequency of the waveguide but also exhibits good rejection, demonstrated by the presence of two transmission zeros with rejection of -16 dB and -19 dB, attained at 7.4 GHz and 14.8 GHz respectively. The proposed SIW BPF was designed using a 0.6mm thick FR4 dielectric substrate measuring 13mm × 15mm. The filter is manufactured to validate the concept and the measured results agree well with the simulation. With all these advantages: compact size, high rejection, and good filtering response, the proposed SIW BPF became suitable for microwave applications.

A highly structured Au-grafted nanoporous gold for surface-enhanced Raman scattering detection of ferbam

The expansive potential of surface-enhanced Raman scattering (SERS) has been well-established; however, the primary bottleneck hindering its routine analytical and commercial implementation is the poor signal reproducibility and challenges in substrate fabrication. Thus, the current work attempts to synthesize a scalable and reproducible nanoporous gold (npAu) decorated with gold (Au) nanoparticles to generate a highly structured Au@npAu nanocomposite. The substrate fabrication completes via three distinct routes: i) selective dealloying to form npAu on the Au film, ii) the fast deposition (i-t = −0.8 V, t = 10.0 s) of Au atoms across the npAu surface, and finally iii) the precise growth control of the generated Au@npAu by a series of by oxidation-reduction cycles (−0.03 to −0.4 V for 80.0 segments at ν = 50.0 mVs−1). The simulations of the dealloyed npAu and the final Au@npAu nanocomposite showed that the reduced interparticle spacing and ligament size in the Au@npAu nanocomposite is crucial for forming abundant "hot spot" regions with highly concentrated electromagnetic fields. The Au@npAu substrate reproducibility was assessed on 400.0 sites for SERS spectral acquisition with a relative standard deviation of 9.22 %. Furthermore, the Au@npAu was checked under different preparation batches for intra- and inter-day analysis and storage for 20.0 days with good stability. Finally, the substrate was checked for direct SERS detection of ferbam residues with a 4.34 × 10−9 mol L−1 sensitivity and examined in real samples with satisfactory recoveries (97.63 ± 1.95%–99.16 ± 0.24 %). This work offers a promising avenue towards highly reproducible, scalable and universal Au@npAu SERS substrate fabrication in diverse SERS-related applications.

Evaluation of the Impact of Parylene C Deposition Method on the Functional Properties of Fabrics.

The article presents the results of research on the impact of the use of an original, innovative method of deposition of Parylene C on the functional properties of fabrics with various potential applications (e.g., thermal and chemical protective clothing, packaging, covers and others). Verification of the effects of the method used was based on interdisciplinary research taking into account the impact of coating fabrics on changes in their structure (micro-CT), surface properties (contact angle), barrier properties (water and chemical liquid wetting), electrostatic properties (charge decay), biophysical properties describing heat and mass transfer (by the Alambeta system and thermal imaging) and flammable properties. Four fabrics made of synthetic organic fibres (meta-aramid, para-aramid) and natural inorganic fibres (basalt) were selected for testing. Given the complex structure of textile substrates, the results confirmed that the two assumed thicknesses of the Parylene C coating were consistent with the actual measurements. The findings indicated that the coatings significantly reduced water and acid absorption in the fabrics compared to unmodified ones. Thermal insulation property tests revealed that coated fabrics exhibited higher thermal conductivity than unmodified fabrics. Additionally, the presence of Parylene C on aramid fabrics resulted in a modest increase in their ignition resistance.

Multivalent-copper-loaded layer-by-layer coating for antibacterial and instantaneous virucidal activity for protective textiles

Nanoarchitectured films are known for tailoring surface properties, while antimicrobial surfaces can reduce pathogen propagation in public spaces and on protective equipment. This study explores the layer-by-layer (LbL) method to create antiviral and antibacterial surfaces against disease transmission. Chitosan and carboxymethylcellulose films were assembled using LbL to incorporate ionic copper, a broad-spectrum antimicrobial agent, onto textile substrates, such as those used in furnishings and personal protective equipment. Film assembly conditions favored the conversion of Cu(II) into multivalent copper, immediately inactivating the MHV-3 virus, Gram-negative (E. coli), and Gram-positive (S. aureus) bacteria. Mechanical tests demonstrate that copper ions have a low impact on the coating and textile physical properties, such as elasticity, tensile strength, and film roughness, by promoting ionic crosslinking of chitosan in the film, while the coating kept air permeability. The coating hydrophilicity and copper release profile were also tuned by the deposition of additional hydrophobic barriers, such as L-alpha-phosphatidylcholine phospholipid or polydimethylsiloxane (PDMS) by spin-coating or plasma polymerization, respectively. Viral inactivation is achieved by the local release of copper ions in contaminated droplets. The coating may also act as a droplet-absorbing barrier, demonstrating the potential of these films for enhancing pathogen resistance and infection control in textile surfaces.

Influence of Textile Substrates on the Adhesion of PJM-Printed MED610 and Surface Morphology

The idea of 3D printing on textile fabrics was first mentioned around 10 years ago and has been investigated in detail since. Originally aimed at opening new design possibilities, combining 3D printing with textile substrates has shifted towards a new method to prepare composites with defined mechanical and other physical properties. The main problem of fused deposition modelling (FDM; also referred to as material extrusion (MEX) according to ISO/ASTM 52900) is printing on textile fabrics, where the frequently insufficient adhesion between both materials has not been fully resolved. For this reason, a few attempts have been made to combine other additive manufacturing methods with textile fabrics. While the principle possibility of using stereolithography (SLA) on textile fabrics was demonstrated a few years ago, PolyJet modelling (PJM) has only recently proven to be applicable for direct printing on textile materials. Here, we present the first study of printing MED610 medical resin on different fabrics. We show that a higher textile fabric surface roughness generally increases the adhesion of the printed material, while a higher hydrophobicity is disadvantageous. We also tested the influence of textile substrates on the porosity of the MED610 surface, as this parameter can influence a material’s potential use in tissue engineering and other biomedical applications.

Improving DNA recovery and sample throughput using the PrepFiler™ Automated Forensic DNA Extraction Kit on two customised Tecan Fluent® 1080 Automated Workstations

One of the primary goals of forensic laboratories performing DNA recovery and profiling is obtaining a high-quality DNA extract from crime scene samples. This is largely dependent on the sensitivity and reliability of the DNA extraction chemistry utilised, as well as the liquid handling and contamination minimisation techniques employed. Automation of DNA extraction methods on large liquid handling platforms allows high-throughput laboratories to apply sensitive chemistries to reliably process a large number of samples, while minimising manual processes and cross-contamination.This study describes the first known implementation of the PrepFiler™ Automated Forensic DNA Extraction Kit on a Tecan Fluent® Gx 1080 Automation Workstation. Two Workstations were customised with the addition of novel “Safe Pipetting Modules” to eliminate sample crossover between wells, which is important in a forensic biology setting to reduce inadvertent DNA transfer. A comparison of DNA extraction efficiency between an optimised PrepFiler™ method and the DNA IQ™ System performed on a Perkin Elmer Janus® Integrator platform showed the optimised PrepFiler™ method consistently extracted a higher yield of DNA from a range of blood inputs, as well as blood and buccal swabs. The PrepFiler™ chemistry also more efficiently removed humic acid and haematin, reducing subsequent PCR inhibition. The subsequent implementation of the optimised PrepFiler™ method onto the Tecan Fluent® Gx workstations showed a further increase in sensitivity, with no evidence of DNA cross-contamination observed. However, the optimised PrepFiler™ method encountered difficulties extracting DNA from fabric substrates, with the PrepFiler Express™ chemistry extracting higher yields on the cartridge-based AutoMate Express™ System.Overall, this study demonstrated the Tecan Fluent® Gx 1080 Automation Workstation is a sensitive, reliable and robust method for DNA extraction using the PrepFiler™ Automated Forensic DNA Extraction Kit, and the addition of the novel Safe Pipetting Module makes this platform an attractive option for forensic biology laboratories where minimising inadvertent DNA transfer is of paramount importance.

Bioinspired Diffuse Reflectance Coatings for Fabric-Based Radiative Coolers

As global temperatures rise due to anthropogenic climate change, thermal comfort becomes an increasingly critical area of research. While most buildings are equipped to cool and heat their interiors, this process is very energy intensive; a smarter approach is to enable personal thermal management using clothing and textiles. In particular, we are interested in the ability to use textiles and clothing to cool bodies in extreme heat, both to maintain comfort and prevent deaths in urban deserts due to heat stroke. One innovative category in this realm is radiative coolers—surfaces adept at manipulating light to passively regulate temperature. These coolers achieve sub-ambient surface temperatures by selectively reflecting or refracting sunlight wavelengths (200nm-2.5µm) while emitting infrared light (8-13µm). This unique capability allows them to maintain cooler temperatures, even when exposed to direct sunlight and the open sky. Coatings facilitating this cooling action typically consist of a porous media filled with refractive gaps, requiring specific substrates and custom production processes, thereby limiting their applications. Furthermore, the necessity of low light transmission presents issues in creating fabrics that radiatively cool while still retaining high breathability and durability. In this study we present a method whereby an optically active coating comprised of a mixture of CaCO3 and BaSO4 microcrystals was applied to multiple fabric substrates to create a radiative cooler. Through the use of photoinitiated chemical vapor deposition (pICVD), a 5 µm thick layer of a hydrophilic polymer polyhydroxyethyleneacrylate (pHEA) was deposited on the fabric substrate. Subsequently, through serial immersion in solutions containing Ca and Ba ions and solutions containing CO3 and SO4 ions, inorganic microcrystals were grown directly on the surface of the fabric. These microcrystals formed with a large polydispersity, endowing the coating with excellent reflective properties in the solar spectrum. Mie scattering calculations confirmed that the CaCO3 and BaSO4 microcrystals were primarily responsible for scattering. Further simulations using finite difference time domain software revealed, surprisingly, that surface-immobilized crystals provided the highest reflection efficiency, indicating that composite fibers with embedded particles are not as efficient. Upon outdoor testing, the device showed a cooling ability of 8°C compared to an uncoated fabric, achieving a maximum cooling of 4°C below ambient temperature. Washing and durability testing of the coating found no degradation in the material's performance, affirming its resilience and long-term effectiveness.

Immobilization of PCET Materials for Electrochemical pH Swing Driven Carbon Capture

Proton-coupled electron transfer (PCET) is a promising method in the realm of carbon capture and release mechanisms. Its fundamental capacity lies in electrochemically inducing pH swings within an aqueous solution, leveraging the high solubility of carbonates in highly alkaline water to capture CO2 and subsequently release iton demand when the aqueous solution is acidified. PCET-based methods promise higher energy efficiency for carbon capture compared to other electrochemical carbon capture methods because they feature fast charge transfer kinetics and can decouple gas-liquid contact and electrochemical activation. In theory, they also allow the use of cheap, widely available small-molecule PCET agents. However, in practice, PCET agents have shown a key limitation that has, thus far, hindered their scalability: oxygen-induced chemical degradation with continued electrochemical cycling. In this work we mitigate the prevailing issue of oxygen sensitivity by immobilizing PCET agents onto a fabric substrate. Via reactive vapor deposition (RVD), porous and conductive films composed of PEDOT-Cl and poly-aminoanthroquinone (PAAQ) are deposited on the surface of a wool felt blend fabric. This approach resulted in the development of a cost-effective, metal-free, and efficient electrode for both capture and release of CO2. Through electrochemical evaluation, the performance of PCET-active quinone moieties present on PAAQ was measured. The overall efficiency of electrochemical capture from gaseous CO2 was found to be 197 kJ/molCO2, substantiating the efficacy of this novel electrode. This work highlights the potential of fabric-immobilized PCET agents and presents a promising avenue towards a sustainable, efficient, and economically viable approach to carbon capture and release technologies.

Textile-Based Membraneless Microfluidic Double-Inlet Hybrid Microbial-Enzymatic Biofuel Cell.

This study reports the development of a textile-based colaminar flow hybrid microbial-enzymatic biofuel cell. Shewanella MR-1 was used as a biocatalyst on the anode, and bienzymatic system catalysts based on glucose oxidase and horseradish peroxidase were applied on an air-breathing cathode to address the overpotential loss in a body-friendly way. A single-layer Y-shaped channel configuration with a double-inlet was adopted. Microchannels of biofuel cells were patterned by silk screen printing with Ecoflex to maintain the flexibility of textile substrates without harm to the human body. The electrodes were fabricated with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate and a mixture of multiwalled carbon nanotubes and single-walled carbon nanotubes by screen printing. The effects of electrode materials, catalyst type, catalyst concentration, and glucose concentration in the catholyte were investigated to optimize the fuel cell performance. The peak power density (44.9 μW cm-2) and maximum current density (388.9 μA cm-2) of the optimized hybrid biofuel cell were better than those of previously reported textile- or paper-substrate microscale single microbial fuel cells. The developed biofuel cell will be a useful platform as a microscale power source that is harmless to the environment and living organisms.

Self-Referenced Au Nanoparticles-Coated Glass Wafers for In Situ SERS Monitoring of Cell Secretion.

Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for discrimination of bimolecules in complex systems. However, its practical applications face challenges such as complicated manufacturing procedures and limited scalability of SERS substrates, as well as poor reproducibility during detection which compromises the reliability of SERS-based analysis. In this study, we developed a convenient method for simultaneous fabrication of massive SERS substrates with an internal standard to eliminate the substrate-to-substrate differences. We first synthesized Au@CN@Au nanoparticles (NPs) which contain embedded internal standard molecules with a single characteristic peak in the Raman-silent region, and then deposited the NPs on 6 mm glass wafers in a 96-well plate simply by centrifugation for 3 min. The one-time obtained 96 SERS substrates have excellent intrasubstrate uniformity and intersubstrate repeatability for SERS detection by using the internal standard (relative standard deviation = 10.47%), and were able to detect both charged and neutral molecules (crystal violet and triphenylphosphine) at a concentration of 10-9 M. Importantly, cells can be directly cultured on glass wafers in the 96-well plate, enabling real time monitoring of the secretes and metabolism change in response to external stimulation. We found that the release of nucleic acids, amino acids and lipids by MDA-MB-231 cells significantly increased under hypoxic conditions. Overall, our approach enables fast and large-scale production of Au@CN@Au NPs-coated glass wafers as SERS substrates, which are homogeneous and highly sensitive for monitoring trace changes of biomolecules.

Textile-Integrated Conductive Layers for Flexible Semiconductor-Based Photovoltaic Structures

This paper presents the results of research on conductive layers dedicated to flexible photovoltaic cells based on semiconductors integrated with a textile substrate. The presented work is part of a broader project aimed at producing flexible solar cells based on the CdTe semiconductor component and manufactured directly on textiles. The research focuses on the selection of textile substrates and contact materials, as well as the methods of their application. This study compares three types of fabrics (basalt, glass, and silicone fibers) and three metals (copper, molybdenum, and silver), evaluating their mechanical and electrical properties. During the experiments, flexible metallic layers with a thickness ranging from 160 to 415 nm were obtained. Preliminary experiments indicated that metallic layers deposited directly on textiles do not provide adequate conductivity, reaching the levels of several hundred Ω/sq and necessitating the introduction of intermediate layers, such as screen-printed graphite. The results show that molybdenum layers on basalt fabrics exhibit the lowest increase in resistance after dynamic bending tests. The obtained relative resistance changes in Mo layers varied from 50% to as low as 5% after a complete set of 200 bending cycles. This article also discusses current challenges and future research directions in the field of textile-integrated photovoltaics, emphasizing the importance of further technological development to improve the energy efficiency and durability of such solutions.

Dielectric and thermal conductive properties of differently structured Ti3C2Tx MXene-integrated nanofibrillated cellulose films

The fabrication of nanocellulose-based substrates with high dielectric permittivity and anisotropic thermal conductivity to replace synthetic thermoplastics in flexible organic electronics remains a big challenge. Herein, films were prepared from native (CNF) and carboxylated (TCNF) cellulose nanofibrils, with and without the addition of thermally conductive multi-layered Ti3C2Tx MXene, to examine the impact of polar (− OH, − COOH) surface groups on the film morphological, moisturizing, dielectric, and thermal dissipation properties. The electrostatic repulsion and hydrogen bonding interaction between the hydrophilic surface/terminal groups on CNF/TCNF and MXene was shown to render their self-assembly distribution and organization into morphologically differently structured films, and, consequently, different properties. The pristine CNF film achieved high intrinsic dielectric permittivity (ε' ~ 9), which was further increased to almost ε' ~ 14 by increasing (50 wt%) the MXene content. The well-packed and aligned structure of thinner TCNF films enables the tuning of both the composite’s dielectric permittivity (ε' ~ 6) and through-plane thermal conductivity (K ~ 2.9 W/mK), which increased strongly (ε' ~ 17) at higher MXene loading giving in-plane thermal conductivity of ~ 6.3 W/mK. The air-absorbed moisture ability of the films contributes to heat dissipation by releasing it. The dielectric losses remained below 0.1 in all the composite films, showing their potential for application in electronics.Graphic abstract

A flexible nanostructured multimodal sensor based on surface plasmon resonance

Biosensors are of great significance for human health and safety monitoring, especially the sensor based on Surface Plasmon Resonance (SPR), widely used in biomolecular detection. Improving its sensitivity has always been the focus of research. In this paper, SPR in grating structures was primarily investigated and then a SPR-based nanoscale metal grating sensor was proposed. With Finite Difference Time Domain (FDTD) simulation, optimization of the sensor's duty ratio, thickness of the Gold (Au) layer, and periodic parameters was conducted. Then sensitivity and quality factor of the sensor are analyzed to obtain the optimal sensor parameters. With a grating period of 0.64 μm, Au layer thickness of 30 nm, and sensor's fill factor of 0.625, the sensor achieves a sensitivity of 0.417 μm/refractive index unit (RIU), demonstrating optimal performance. Additionally, Abaqus tensile simulations were performed on the grating imprinting section, validating the uniformity and consistency of strain in the Polydimethylsiloxane (PDMS) substrate-Au film grating structure during stretching. Finally, a combination mold based on acrylic material is designed, effectively addressing the challenging demolding characteristics of cured PDMS material, offering an efficient manufacturing approach for PDMS substrate fabrication. The SPR-based nanoscale grating multimodal sensor designed in this paper exhibits high sensitivity and potential cost-effectiveness in protein molecule detection and flexible stress-strain sensing applications, revealing promising broad prospects for practical utilization.

Effect of optical and electronic structure on the photocatalytic activity of Al doped ZnO ALD thin films on glass fibers

Photocatalytic water treatment can be promising for eliminating toxic pollutants via a more sustainable approach using renewable sources. However, the technique still requires materials design to optimize/maximize the performance of the photocatalytic materials. Immobilizing the thin film photocatalytic materials onto high surface area textile substrates via atomic layer deposition (ALD) can offer a practical design approach. Al-doped ZnO (AZO) ALD films are deposited onto glass fabric substrates, and their photocatalytic performances were investigated in relation to the FESEM, XRD, XPS, UV–Vis, and PL characterizations. The amount of Al and the post-deposition annealing changed the materials structure, thus the photocatalytic activity of the films. Maximum performance was achieved with the 20 % Al-doped ZnO films after a post-deposition thermal annealing step at 450 °C. The sample also showed the highest UV–Vis absorption and PL emission among the samples. However, this sample didn’t show any crystal peaks in the XRD analysis. Furthermore, the charge carrier concentrations and the mobility of the films were investigated via Hall-Effect, which showed that the 20 % AZO sample has very different features with a p-type nature compared to the other AZO films.

Printing and dyeing of halloysite nano clay hybrid with natural chlorophyll dye on cotton fabric

This work deals with the synthesis of hybrids formed by the natural dye chlorophyll and halloysite for their subsequent application in the textile field. Once the pigments have been synthesized, with 98 % adsorption, they are used for two textile colouring functions, namely printing and dyeing. In both cases, satisfactory and interesting results were obtained. The hybrids were characterized by FTIR, XRD, TGA, SEM-EDX, BET and all the appropriate colour measurements were carried out to obtain the coordinates in CIELAB space and also to know their total solar reflectance (TSR) 45.98 %. In addition, statistical techniques were used with the use of ANOVA to evaluate the results obtained. The dyeing was carried out by exhaustion and its use was compared with the use of nibbled and non-nibbled fabrics. The textiles were tested for fastness and the results are presented in instrumentally obtained grey scale values, achieving in some cases values of 4–5. Thus, the chlorophyll adsorption capacity of halloysite and its stabilisation for subsequent application in printing and dyeing processes on textile substrates has been demonstrated. This process could be scalable at an industrial level.