Fabrication Of Substrates Research Articles

Citric acid-crosslinked nanosilver finishing of indigo-dyed denim for potential surgical gowns

Purpose This paper aims to develop an indigo-dyed denim fabric treated with a nanosilver colloid in the presence of a natural crosslinker of citric acid for possible surgical gown fabrication applications. Design/methodology/approach A bleached denim fabric was dyed with the sustainable indigo dye followed by silver nanofinishing through citric acid crosslinking under the pad-dry-cure method. The prepared denim samples were analyzed for chemo-physical, textile, dyeing, antibacterial and finish release properties. Findings The results demonstrated that the comfort and textile characteristics of nanosilver-treated/indigo-dyed cellulosic fabric were affected due to the crosslinking, surface amphiphilicity and air permeability. These properties were, still, in the acceptable range for the fabrication of naturally dyed and antibacterial nanofinished denim gowns. Practical implications The dyeing of denim with synthetic dyes may cause harmful effects on the skin and health of the wearer, and the authors present an eco-friendly sustainable approach. Originality/value The authors used the fabric substrate, natural indigo dye and reducing/crosslinker agent of citric acid, all being bio-based, in the fabrication of antibacterial dyed fabric for health care garments.

Eradication of Gram-negative bacteria by reusable carbon nitride-coated cotton under visible light

A metal-free graphitic carbon nitride (GCN-T) photocatalyst obtained through a microwave-assisted technique was immobilised on cotton fabrics by an exhaustion method. Coated-cotton with only 0.81 % (w/w) of GCN-T (CO/GCN-T) presented effective antimicrobial properties against pathogenic bacteria, P. aeruginosa and E. coli, eradicating the retained bacteria after 60 min of direct irradiation with visible light. The self-cleaning activity of CO/GCN-T samples was also proved for the degradation of Rhodamine B (RhB) stains after 60 min of irradiation with a cost-effective Light Emitting Diode (LED) (λmax = 417 nm). In addition, CO/GCN-T did not hinder the growth of commensal skin bacteria Staphylococcus spp. and presented non-cytotoxicity to skin cell lines, such as fibroblasts (L929) and keratinocytes (HaCaT), so it can be stated that these textiles are promising for applications in direct contact with the skin. Therefore, these are relevant findings since a textile substrate, with the ability to remove or eliminate harmful microorganisms, is an asset for the healthcare area.

Recent development and challenges on design and fabrication of flexible substrate based carbon monoxide gas sensor: a review

PurposeSensing technology has been extensively researched and used due to its applications in industrial production and daily life. Due to inherent limitations of conventional silicon-based technology, researchers are now-a-days paying more attention to flexible electronics to design low-cost, high-sensitivity devices. This observational and analytical study aims to emphasis on carbon monoxide gas sensor. This review also focuses the challenges faced by flexible devices, offers the most recent research on paper-based gas sensors and pays special focus on various sensing materials and fabrication techniques.Design/methodology/approachTo get the better insight into opportunities for future improvement, a number of research papers based on sensors were studied and realized the need to design carbon monoxide gas sensor. A number of parameters were then gone through to decide the flexibility parameter to be considered for design purposes. This review also focuses on the challenges faced by flexible devices and how they can be overcome.FindingsIt has been shown that carbon monoxide gas, being most contaminated gas, needs to be fabricated to sense low concentration at room temperature, considering flexibility as an important parameter. Regarding this parameter, some tests must be done to test whether the structure sustains or degrades after bending. The parameters required to perform bending are also described.Originality/valueDue to inherent limitations of conventional silicon-based technology, now-a-days attention is paid towards flexible electronics to design low-cost, high-sensitivity devices. A number of research articles are provided in the literature concerning gas sensing for different applications using several sensing principles. This study aims to provide a comprehensive overview of recent developments in carbon monoxide gas sensors along with the design possibilities for flexible paper-based gas sensors. All the aspects have been taken into consideration for the fabrication, starting with paper characterization techniques, various sensing materials, manufacturing methodologies, challenges in the fabrication of flexible devices and effects of bending and humidity on the sensing performance.

Tunable Layered Gold Nanochips for High Sensitivity and Uniformity in SERS Detection

Reasonable design and controllable fabrication of plasmonic substrates are the keys to achieving surface-enhanced Raman spectroscopy (SERS) detection with high sensitivity and uniformity. The coupling of the two main modes of surface plasmon, the localized surface plasmon resonance (LSPR) mode and the surface plasmon polariton (SPP) mode, has been proven to be an appealing way to obtain excellent SERS responses. Nevertheless, it remains an obstacle to further improve the LSPR-SPP coupling efficiency due to the dramatic nonuniformity of the nanostructure obtained by traditional wet chemical methods. Here, we report a controllable electron-beam lithography (EBL) process for the fabrication of layered Au nanochips. For the optimized Au CFN (cap and film nanostructure) structure, benefiting from the remarkable electric field enhancement induced by the effective LSPR-SPP coupling at the junction of the Au cap and Au film structure, an improved SERS performance with an enhancement factor (EF) of 2.8 × 106 and a low detection limit of 10–13 M are achieved using 4-nitrothiophenol (4-NTP) as the probe molecule. In addition, the Au CFN substrate exhibits a high uniformity over a large area. Such a new strategy for the design of plasmonic substrates with superior LSPR-SPP coupling can be applied in various SERS detection scenarios.

Interactions between Ionic Cellulose Derivatives Recycled from Textile Wastes and Surfactants: Interfacial, Aggregation and Wettability Studies.

Interactions between polymers (P) and surfactants (S) in aqueous solution lead to interfacial and aggregation phenomena that are not only of great interest in physical chemistry but also important for many industrial applications, such as the development of detergents and fabric softeners. Here, we synthesized two ionic derivatives-sodium carboxymethylcellulose (NaCMC) and quaternized cellulose (QC)-from cellulose recycled from textile wastes and then explored the interactions of these polymers with assorted surfactants-cationic (CTAB, gemini), anionic (SDS, SDBS) and nonionic (TX-100)-commonly used in the textile industry. We obtained surface tension curves of the P/S mixtures by fixing the polymer concentration and then increasing the surfactant concentration. In mixtures where polymer and surfactant are oppositely charged (P-/S+ and P+/S-), a strong association is observed, and from the surface tension curves, we determined the critical aggregation concentration (cac) and critical micelle concentration in the presence of polymer (cmcp). For mixtures of similar charge (P+/S+ and P-/S-), virtually no interactions are observed, with the notable exception of the QC/CTAB system, which is much more surface active than the neat CTAB. We further investigated the effect of oppositely charged P/S mixtures on hydrophilicity by measuring the contact angles of aqueous droplets on a hydrophobic textile substrate. Significantly, both P-/S+ and P+/S- systems greatly enhance the hydrophilicity of the substrate at much lower surfactant concentrations than the surfactant alone (in particular in the QC/SDBS and QC/SDS systems).

Substrate effect and structure optimization of fabric-based circularly polarized dipole antenna for radio frequency energy harvesting

Radio frequency energy harvesting on textiles is seen as a method of enabling sustainable battery-free operation for wearable devices, while few works have clarified the influence of fabric properties on antenna performance. To prepare successfully a fabric-based circularly polarized antenna for radio frequency energy harvesting, this paper will clarify the effect of key fabric characteristics (such as dielectric properties and fabric thickness) on antenna performance by a finite element simulation. The simulated results showed the antenna resonant frequency is inversely proportional to the half square of the fabric’s dielectric constant, and the antenna radiation efficiency and gain are inversely proportional to the square of its dielectric loss tangent and thickness. Then, for the typical fabric substrates, the structure parameters of the existing circularly polarized antenna are optimized to work in the expected working frequency band, and the dominating structure parameter of the antenna in performance was identified. The optimized antenna prototype has excellent performance. The antenna has a bandwidth of 350 MHz and a maximum transmission distance of 190 cm. The received signal strength indication per unit area is 2.35 mW/cm2 and the output voltage is 1.19 mV/cm2 at a distance of 100 cm. It is concluded that the flexible size-minimized wide bandwidth circularly polarized radio frequency energy harvesting antenna screen-printed on fabric was derived from a commercial circularly polarized antenna with fiber-reinforced epoxy plate (FR4) substrate, and the critical geometrical and material parameters of the fabric substrate for this antenna performance as well as the affecting mechanism were identified.

A comparative performance of antibacterial effectiveness of copper and silver coated textiles

During current COVID-19 crises, the antimicrobial textiles primarily those utilized in hospital by doctors and paramedical staff have become increasingly important. Thus, there is an unmet requirement to develop antimicrobial textiles for infection control and hygiene practices. Metallic nanoparticles exhibit great effectiveness towards resistant microbial species making them a potential solution to the increasing antibiotic resistance. Due to this, nanoparticles particularly copper and silver have become most prevalent forms of antibacterial finishing agents for the development of antimicrobial textiles. This review is mainly focused on the significance of copper and silver nanoparticles for the development of antimicrobial textiles. The comparative analysis of the antibacterial effectiveness of copper and silver nanoparticles as well as the possible physical and chemical interactions responsible for their antibacterial action are explained. The negative impact of pathogenic microbes on textiles and possible interactions of antimicrobial agents with microbes have also been highlighted. The significance of nanotechnology for the development of antimicrobial textiles and their applications in medical textiles domain have also been discussed. Various green synthesis and chemical methods used for the synthesis of Ag and Cu nanoparticles and their application on textile substrates to impart antimicrobial functionality have also been discussed. The various qualitative and quantitative standard testing protocols utilised for the antimicrobial characterization of textiles have also discussed in this review. The developed Cu and Ag coated textiles could be effectively applied in the field of hospital textiles for the preparation of antibacterial scrub suits, surgical gowns, panel covers, protective clothing, bedding textiles, coveralls, wound dressings, table covers, curtains, and chair covers etc.

Stretchable Ink Printed Graphene Device with Weft-Knitted Fabric Substrate Based on Thermal-Acoustic Effect

Thermal-acoustic devices have great potential as flexible ultrathin sound sources. However, stretchable sound sources based on a thermal-acoustic mechanism remain elusive, as realizing stable resistance in a reasonable range is challenging. In this study, a stretchable thermal-acoustic device based on graphene ink is fabricated on a weft-knitted fabric. After optimization of the graphene ink concentration, the device resistance changes by 8.94% during 4000 cycles of operation in the unstretchable state. After multiple cycles of bending, folding, prodding, and washing, the sound pressure level (SPL) change of the device is within 10%. Moreover, the SPL has an increase with the strain in a specific range, showing a phenomenon similar to the negative differential resistance (NDR) effect. This study sheds light on the use of stretchable thermal-acoustic devices for e-skin and wearable electronics.

Silk textile finished with natural dyes and UV resistance agents from agricultural waste Aloe vera rinds

Aloe vera is an agricultural resource widely used in many fields, but it has not been fully exploited as a biological dye in textile substrates. This work explored an approach for using Aloe vera rinds (AVRs) for the simultaneous dyeing and UV-protective functional finishing of silk fabrics. The optimal extraction conditions and the chemical composition of Aloe vera dye (AVD) were investigated. The colour parameters, colour-fastness, and UV-protective properties of silk fabrics dyed with AVD were tested. The results showed that the extracts mainly included polyphenols and flavonoids. The dyed fabrics obtained a colour depth (K/S) of 7.9447 and > 4 grades of colour-fastness to washing and rubbing without using a mordant. The dyed fabrics exhibited a surprising ultraviolet protection factor (UPF) of 2075.76 and remained at 1241.23 after 25 washing cycles, which was much higher than standard recommended. This research provides a method for the value-added management of agricultural waste for natural dyeing and functional finishing of textiles.

Intermediate annealing and strong cube texture of Ni-5at.%W alloy thin substrates for YBCO coated conductors

In this work, a series of studies have been carried out on ultra-thin Ni-5at%W (Ni5W) alloy substrates used for the coated conductors. The ultra-thin Ni5W alloy substrate can be fabricated for the large square REBCO film with a size of over 40 mm × 40 mm, which is normally used in scenarios to support a magnetic field in a specific area. To obtain a stronger recrystallized cubic texture, the intermediate annealing was added to optimize the rolling texture during the rolling process of the Ni5W alloy substrate. A typical copper-type rolling texture was obtained in the substrate which intermediate annealed at 96.25%, and the cube texture reached 97.6% after annealing recrystallization. Moreover, The deformation and recrystallization of 40 μm thick Ni-5at%W (Ni5W) alloy thin substrates were investigated by the quasi-in situ method. The fabrication of ultra-thin Ni5W substrates increases the potential of miniaturizing lightweight coated conductors, which helps to further promote and accelerate the manufacturing process of the entire coated conductor strip.

Fabrication of flexible SERS substrate based on Au nanostars and PDMS for sensitive detection of Thiram residue in apple juice

We developed a novel fabrication of flexible surface-enhanced Raman scattering (SERS) substrate to perform selective and sensitive determination of thiram residue in fruits and juices. Au nanostars (Au NSs) with multi-branching structure were self-assembled on aminated Polydimethylsiloxane (PDMS) slides by electrostatic interaction. By measuring the Thiram’s characteristic peak intensity at 1371 cm−1, the SERS method could distinguish Thiram from other pesticide residues. A good linear relationship between the peak intensity at 1371 cm−1 and thiram’s concentration was established at the range from 0.01 ppm to 100 ppm and the Limit of detection is 0.0048 ppm. We directly used this SERS substrate to detect Thiram in apple juice. By standard addition method, recoveries varied in the range of 97.05% to 106.00% and the RSD were from 3.26% to 9.35%. The SERS substrate exhibited a good sensitivity, stability and selectively for the detection of Thiram in food samples, which can be spread as a common method for the detection of pesticides in food samples.

Fabrication of wafer-scale ordered micro/nanostructures for SERS substrates using rotational symmetry cantilever-based probe lithography

Surface-enhanced Raman spectroscopy (SERS) is considered as a powerful analytical tool with a fingerprint-level resolution. Nevertheless, it is still challenging to fabricate large-area, sensitive, and reproducible SERS substrates through facile and cost-effective process. Herein, a novel double-layer rotational symmetry cantilever (DRSC)-based probe lithography was proposed for the facile and cost-effective fabrication of wafer-scale ordered micro/nanostructures towards SERS applications. Using finite element simulation, the architecture of DRSC was optimized, and its strength and fatigue were checked. Several typical fabrication parameters were evaluated using the DRSC-based probe lithography. The results indicated that the proposed lithography exhibited identical stiffness in all horizontal directions, and can effectively suppress the horizontal drift and achieve high-precision fabrication under the condition of high-speed reciprocating processes. Several high-quality micro/nanostructures were achieved to demonstrate its excellent ability in large-area and high-precision fabrication. SERS spectra of malachite green (MG) indicated an impressive enhancement, excellent stability, and high reproducibility (including intra-substrate and batch-to-batch sampling), and practical applications of prepared SERS substrates were demonstrated by detecting MG residues from various water environments and fish scales. This study provides a promising approach for the facile and cost-effective fabrication of large-area, sensitive, and reproducible SERS substrates.

Development of wideband CPW‐fed microstrip patch antenna on textile substrate

AbstractA wideband flexible coplanar microstrip patch (CPW) antenna is developed on a felt substrate to radiate from 1.4 to 3 GHz. The dimension of the antenna is 0.37λ × 0.37λ × 0.007λ, developed on felt, which is a flexible textile material with a 1.38 dielectric constant. The patch and ground are printed on the same side of the substrate, where a semi‐circular slot is etched on the patch, and symmetric slots are etched on the ground to achieve wide bandwidth (73%). CPW feed impedance is matched with the connector impedance using the modified feed line. The felt antenna has a measured peak gain of 4.7 dB at 2.45 GHz. Moreover, the performance of the textile antenna under different bending conditions are experimentally carried out. The antenna bandwidth is reduced due to a decrease in bending angle, but still, the antenna operates at the required bandwidth of 1.8–2.9 GHz (upto 80 mm radius).

Transfer and persistence studies of inorganic and organic gunshot residues using synthetic skin membranes

The complex nature of gunshot residue (GSR) transfer and persistence introduces challenges and skepticism in its evidential value. Therefore, this work evaluates the behavior and movement of inorganic and organic gunshot residues to assist in the evidence interpretation. The study encompassed over 650 samples, including 247 collections from human skin after firing a gun and 405 synthetic skin and fabric substrates after depositing a characterized pGSR/OGSR standard. Transfer and persistence experiments were evaluated on different substrates (hands, ears, nostrils, forehead, hair, fabrics, and synthetic skin), at different times after firing (0 to 6 h), and common post-shooting activities (rubbing hands, handshaking, running, washing hands and fabrics). Ground truth knowledge of particle counts and analyte concentrations was used to calculate the recovery for inorganic and organic constituents from clothing and a synthetic skin membrane (StratM®). Authentic shooter skin samples were compared to synthetic skin to establish the validity of skin-substitute models. During controlled experiments, inorganic particles persisted longer than OGSR on inactive samples (9% and < 25% loss at 6 hrs, respectively), but inorganic particles were more prone to secondary transfer than OGSR (up to 35% vs. 0% transfer, respectively). High percentages of particles were lost during vigorous activities like washing hands (99% loss) or rubbing hands (55% loss). In comparison, less loss was observed during the same studies for OGSR (<21%). This study offers a deeper understanding of gunshot residue transfer and persistence mechanisms that can assist analysts and investigators in improving sample collection and interpretation of evidence.

Research progress on the substrate for metal–organic framework (MOF) membrane growth for separation

During the last decade, metal–organic frameworks (MOFs) have been applied in various fields due to their unique chemical and functional advantages. One of the widespread research hotspots is MOF-based membranes for separations, specifically continuous defect-free MOF membranes, which are usually grown on porous substrates. The substrate not only serves as the MOF layer support but also has a great influence on the membrane fabrication process and the final separation performance of the resultant membrane. In this review, we mainly introduce the progress focused on the substrates for MOF membranes fabrication. The substrate modifications and seeding methods aimed at synthesizing high-quality MOF membranes are also summarized systematically.

Control of UV-Curing Ink Splashing and Line Quality during DC-Pulse-Modulated Electrohydrodynamic Printing for Textile-Based Electronics

The DC pulse-modulated electrohydrodynamic (EHD) printing technique enables one-step formability of electronic components of electronic textiles. However, the common fabrics as a kind of insulating substrate inevitably come into serious ink splashing behavior during printing, which will severely deteriorate the quality of printed patterns. To solve this problem, the reason for ink splashing on the polyester woven fabric was experimentally clarified, and then a facile solution, that is, the mature antistatic finishing technique in the textile industry, was used to dissipate residual charges emerging on insulating fabric substrates. The relationship between the ink splashing behavior and the electrostatic half-life of fabric was investigated. Also, the feasibility of antistatic finishing for overcoming ink splashing was evaluated. Results show that ink splashing is solved, and the standard deviation of line width is within 3% at a half-life of less than 0.2 s. Moreover, there is no significant effect of antistatic finishing on electrical resistance and adhesion performance of printed lines, and the finishing even with a dilution ratio of 1:100 did not disturb the port impedance of the printed antenna. This strategy is expected to promote the practice of the EHD printing technique in the large-scale and low-cost fabrication of wearable electronic textiles compatible with most of the common fabric substrates.

Developing highly reliable SERS substrates based on Ag grown on alumina nanomeshes anodized under 1 V for efficiently sensing Raman-active molecules

We have developed silver-nanostructures grown on anodic alumina nanomesh (AAN) films to create new-type substrates for surface-enhanced Raman scattering (SERS). AAN with uniform thin sidewall of ∼ 5 nm was fabricated by anodizing Al sheets at 1 V in 6% H3PO4 solution. Subsequent AC electrochemical deposition of silver created an array of nanoparticles or nano-islands depending on growth time. The particle-island transition is non-monotonic evolution, since metal growth and dissolution compete in AC electrodeposition process. Systematic SERS study on various Ag-AAN films with trial probes of adenine solutions reveals collective contribution of electron-plasma oscillation and surface area of silver nanostructures in Raman enhancements. SERS signals are primarily contributed by surface area under excitation wavelength of 532 nm (away from plasmonic resonance). The average correlation coefficient between the SERS intensity and surface area was 0.85, indicating robust correlation. This value was reduced to 0.61 under excitation wavelength of 633 nm (closer to plasmonic resonance). Furthermore, increased Ag-deposition reduced the relative standard deviation of SERS intensities and thus improved both the uniformity and quality consistency of SERS substrates. Therefore, fabrication of SERS substrate with larger Ag surface area under similar SERS enhancement factors is suggested for high throughput in commercial sectors.

Development and Optimization of 3D-Printed Flexible Electronic Coatings: A New Generation of Smart Heating Fabrics for Automobile Applications.

Textile-based Joule heaters in combination with multifunctional materials, fabrication tactics, and optimized designs have changed the paradigm of futuristic intelligent clothing systems, particularly in the automobile field. In the design of heating systems integrated into a car seat, conductive coatings via 3D printing are expected to have further benefits over conventional rigid electrical elements such as a tailored shape and increased comfort, feasibility, stretchability, and compactness. In this regard, we report on a novel heating technique for car seat fabrics based on the use of smart conductive coatings. For easier processes and integration, an extrusion 3D printer is employed to achieve multilayered thin films coated on the surface of the fabric substrate. The developed heater device consists of two principal copper electrodes (so-called power buses) and three identical heating resistors made of carbon composites. Connections between the copper power bus and the carbon resistors are made by means of sub-divide the electrodes, which is critical for electrical-thermal coupling. Finite element models (FEM) are developed to predict the heating behavior of the tested substrates under different designs. It is pointed out that the most optimized design solves important drawbacks of the initial design in terms of temperature regularity and overheating. Full characterizations of the electrical and thermal properties, together with morphological analyses via SEM images, are conducted on different coated samples, making it possible to identify the relevant physical parameters of the materials as well as confirm the printing quality. It is discovered through a combination of FEM and experimental evaluations that the printed coating patterns have a crucial impact on the energy conversion and heating performance. Our first prototype, thanks to many design optimizations, entirely meets the specifications required by the automobile industry. Accordingly, multifunctional materials together with printing technology could offer an efficient heating method for the smart textile industry with significantly improved comfort for both the designer and user.

Enhancing Physiochemical Substrate Properties of Thin-Film Composite Membranes for Water and Wastewater Treatment via Engineered Osmosis Process

The commercial thin-film composite (TFC) nanofiltration (NF) membrane is unsuitable for engineered osmosis processes because of its thick non-woven fabric and semi-hydrophilic substrate that could lead to severe internal concentration polarization (ICP). Hence, we fabricated a new type of NF-like TFC membrane using a hydrophilic coated polyacrylonitrile/polyphenylsulfone (PAN/PPSU) substrate in the absence of non-woven fabric, aiming to improve membrane performance for water and wastewater treatment via the engineered osmosis process. Our results showed that the substrate made of a PAN/PPSU weight ratio of 1:5 could produce the TFC membrane with the highest water flux and divalent salt rejection compared to the membranes made of different PAN/PPSU substrates owing to the relatively good compatibility between PAN and PPSU at this ratio. The water flux of the TFC membrane was further improved without compromising salt rejection upon the introduction of a hydrophilic polydopamine (PDA) coating layer containing 0.5 g/L of graphene oxide (PDA/GO0.5) onto the bottom surface of the substrate. When tested using aerobically treated palm oil mill effluent (AT-POME) as a feed solution and 4 M MgCl2 as a draw solution, the best performing TFC membrane with the hydrophilic coating layer achieved a 67% and 41% higher forward osmosis (FO) and pressure retarded osmosis (PRO) water flux, respectively, compared to the TFC membrane without the coating layer. More importantly, the coated TFC membrane attained a very high color rejection (>97%) during AT-POME treatment, while its water flux and reverse solute flux were even better compared to the commercial NF90 and NF270 membranes. The promising outcomes were attributed to the excellent properties of the PAN/PPSU substrate that was coated with a hydrophilic PDA/GO coating and the elimination of the thick non-woven fabric during TFC membrane fabrication.

Experimental Investigations on the Effect of Textile Substrate Nanomaterial Coating on Wearable Antenna Performance

Experimental Investigations on the Effect of Textile Substrate Nanomaterial Coating on Wearable Antenna Performance