Surface modification of polyester using chicken feather keratin hydrolysate to improve water absorbency and dye uptake

PET fiber has an intrinsic low hydrophilic character and an inactive surface which make it uncomfortable for wearing purpose. Moreover, it is difficult to colour polyester fabric other than disperse dyes. Therefore, surface modification of PET is very important to improve its absorbency and bring the possibility to dye polyester with anionic dyes by altering its surface characteristics. This research was focused on surface modification of polyester using chicken feather which involves serine as the most abundant amino acid with hydroxyl groups. The treated polyester fabric using 20ml/L concentration of chicken feather extract showed improved water drop absorbency from 45 into 3 seconds and the reactive dye uptake by 36 folds from 0.15 to 5.37 K/S values

A washable silver-printed textile electrode for ECG monitoring

Electrocardiography (ECG) is one of the most widely used diagnostic methods to examine the development of cardiovascular diseases (CVD). It is important to have a long-term continuous ECG recording to properly monitor the heart activity, which can be measured by placing two or more electrodes on the skin. Ag/AgCl gelled electrodes are often used for the ECG measurement, but they are not suitable for long-term monitoring due to the dehydration of the gel over time and skin irritation. Textile-based electrodes could have an important role in replacing the gelled electrodes and avoid their associated problems. This paper focuses on the development of a textile-based electrode and studying its ECG detecting performance. We developed silver printed textile electrodes via a flat-screen printing of silver ink on knitted polyester fabric. The surface resistance of silver-coated PET fabric was 1.78 Ω/sq and 3.77 Ω/sq before and after washing, respectively. Stretching of the conductive fabric from 5% to 40% caused a 6% to 18.28% increase in surface resistance. The silver-printed PET fabric stayed reasonably conductive after washing and stretching which makes it suitable for wearable applications. Moreover, the ECG measurement at static condition showed that the signal quality collected before and after washing were comparable with the Ag/AgCl standard electrodes. The P, QRS, T waveforms, and heartbeat before washing in respective order were 0.09 mV, 1.20 mV, 0.30 mV for the silver printed fabric electrode and 72 bpm, and 0.10 mV, 1.21 mV, 0.30 mV, and 76 bpm for Ag/AgCl standard electrode

Development of a flex and stretchy conductive cotton fabric via flat screen printing of PEDOT : PSS/PDMS conductive polymer composite

In this work, we have successfully produced a conductive and stretchable knitted cotton fabric by screen printing of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and poly(dimethylsiloxane-b-ethylene oxide)(PDMS-b-PEO) conductive polymer composite. It was observed that the mechanical and electrical properties highly depend on the proportion of the polymers, which opens a new window to produce PEDOT:PSS-based conductive fabric with distinctive properties for different application areas. The bending length analysis proved that the flexural rigidity was lower with higher PDMS-b-PEO to PEDOT:PSS ratio while tensile strength was increased. The SEM test showed that the smoothness of the fabric was better when PDMS-b-PEO is added compared to PEDOT:PSS alone. Fabrics with electrical resistance from 24.8 to 90.8 k ohm/sq have been obtained by varying the PDMS-b-PEO to PEDOT:PSS ratio. Moreover, the resistance increased with extension and washing. However, the change in surface resistance drops linearly at higher PDMS-b-PEO to PEDOT:PSS ratio. The conductive fabrics were used to construct textile-based strain, moisture and biopotential sensors depending upon their respective surface resistance

Development of washable silver printed textile electrodes for long-term ECG monitoring

Long-term electrocardiography (ECG) monitoring is very essential for the early detection and treatment of cardiovascular disorders. However, commercially used silver/silver chloride (Ag/AgCl) electrodes have drawbacks, and these become more obvious during long-term signal monitoring, making them inconvenient for this use. In this study, we developed silver printed textile electrodes from knitted cotton and polyester fabric for ECG monitoring. The surface resistance of printed electrodes was 1.64 Ω/sq for cotton and 1.78 Ω/sq for polyester electrodes. The ECG detection performance of the electrodes was studied by placing three electrodes around the wrist where the electrodes were embedded on an elastic strap with Velcro. The ECG signals collected using textile electrodes had a comparable waveform to those acquired using standard Ag/AgCl electrodes with a signal to noise ratio (SNR) of 33.10, 30.17, and 33.52 dB for signals collected from cotton, polyester, and Ag/AgCl electrodes, respectively. The signal quality increased as the tightness of the elastic strap increased. Signals acquired at 15 mmHg pressure level with the textile electrodes provided a similar quality to those acquired using standard electrodes. Interestingly, the textile electrodes gave acceptable signal quality even after ten washing cycles

Integration of conductive materials with textile structures : an overview

In the last three decades, the development of new kinds of textiles, so-called smart and interactive textiles, has continued unabated. Smart textile materials and their applications are set to drastically boom as the demand for these textiles has been increasing by the emergence of new fibers, new fabrics, and innovative processing technologies. Moreover, people are eagerly demanding washable, flexible, lightweight, and robust e-textiles. These features depend on the properties of the starting material, the post-treatment, and the integration techniques. In this work, a comprehensive review has been conducted on the integration techniques of conductive materials in and onto a textile structure. The review showed that an e-textile can be developed by applying a conductive component on the surface of a textile substrate via plating, printing, coating, and other surface techniques, or by producing a textile substrate from metals and inherently conductive polymers via the creation of fibers and construction of yarns and fabrics with these. In addition, conductive filament fibers or yarns can be also integrated into conventional textile substrates during the fabrication like braiding, weaving, and knitting or as a post-fabrication of the textile fabric via embroidering. Additionally, layer-by-layer 3D printing of the entire smart textile components is possible, and the concept of 4D could play a significant role in advancing the status of smart textiles to a new level

Wearable smart textiles for long-term electrocardiography monitoring : a review

The continuous and long-term measurement and monitoring of physiological signals such as electrocardiography (ECG) are very important for the early detection and treatment of heart disorders at an early stage prior to a serious condition occurring. The increasing demand for the continuous monitoring of the ECG signal needs the rapid development of wearable electronic technology. During wearable ECG monitoring, the electrodes are the main components that affect the signal quality and comfort of the user. This review assesses the application of textile electrodes for ECG monitoring from the fundamentals to the latest developments and prospects for their future fate. The fabrication techniques of textile electrodes and their performance in terms of skin–electrode contact impedance, motion artifacts and signal quality are also reviewed and discussed. Textile electrodes can be fabricated by integrating thin metal fiber during the manufacturing stage of textile products or by coating textiles with conductive materials like metal inks, carbon mate-rials, or conductive polymers. The review also discusses how textile electrodes for ECG function via direct skin contact or via a non-contact capacitive coupling. Finally, the current intensive and promising research towards finding textile-based ECG electrodes with better comfort and signal quality in the fields of textile, material, medical and electrical engineering are presented as a perspective

Design and fabrication of textile-based dry electrodes for ECG monitoring

Met de snelle ontwikkeling in technologie en de steeds toenemende eisen van mensen, wordt van textiel verwacht dat het naast het warm en comfortabel maken van mensen ook extra functionaliteiten vertoont. Dit leidde tot de ontwikkeling van "slim textiel" (smart textile). Slim textiel zijn materialen die hun gedrag kunnen veranderen als reactie op de invloed van externe factoren. Hoewel draagbaar slim textiel op alle gebieden van ons leven kan worden gebruikt, is de gezondheidszorg het meest opmerkelijke marktgebied. Draagbare medische apparaten kunnen verschillende elektrische fysiologische activiteiten bewaken. Dit onderzoek richt zich op de ontwikkeling van textielelektroden voor ECG-monitoring, het vergelijken van hun prestaties en het ontwerpen van een draagbaar ECG-monitoringsysteem door ontwikkelde elektroden te integreren in een in de handel verkrijgbare schouderband. De ECG-acquisitieprestaties van de ontwikkelde elektroden onder verschillende situaties werden bestudeerd. De ontwikkelde textielelektroden zijn met succes gebruikt voor ECG-monitoring (van mens en dier) en de verkregen resultaten hebben aangetoond dat de elektroden het potentieel hebben om de commerciële Ag/AgCl-elektroden voor langdurige ECG-bewaking te vervangen. De ontwikkelde elektroden zijn in staat ECG-signalen op te vangen, zowel in statische als dynamische omstandigheden, en de signaalkwaliteit neemt toe met een toename van de elektrodegrootte en houddruk

Skin-electrode impedance characterization of textile-based ECG electrodes

Electrodes are the main components in monitoring and recording electrocardiogram (ECG) signals. Selecting the right type of electrode is required during ECG monitoring which is the main factor that affects the quality of the acquired signals. Electrode-skin impedance is a key indicator of electrode performance. Skin-electrode impedance test is very important to evaluate whether the electrodes can be able to use for recording bioelectric because if the skin-electrode impedance is too high it means the electrodes cannot be used for ECG recording. The performance of electrodes in detecting biopotential signals is highly dependent on electrode-skin impedance. In this work, we have developed silver-based textile ECG electrodes by embroidering a 29-tex silver-plated polyamide yarn having a 136 Ω/m resistance on cotton fabric at 1.5 mm stitch length and screen printing of silver ink (Metalon HPS-FG32) having a solid content of 75% and particle size 1.5 Micron on cotton fabric. The electrode-skin impedance and ECG detection performance of the electrodes were studied and the results were compared with standard Ag/AgCl electrodes. Skin-electrode impedance was measured using IVIUM potentiostat with a three-electrode configuration by wrapping the same type of electrodes on the subject's forearm using an elastic strap. To investigate the effect of strap tightness on stability and skin-electrode impedance, testing was carried out at 12 mmHg, 18 mmHg, and 24 mmHg contact pressure. The standard Ag/AgCl electrodes show lower impedance than dry textile electrodes due to the presence of conductive gel in such electrodes. Comparatively, embroidered textile electrodes show lower impedance than silver printed electrodes. It was observed that the skin impedance decreased with an increase in contact pressure, which would reveal that the performance of the electrodes becomes improved with an increase in strap tightness. The ECG detection performance of the electrodes was studied by placing the measuring electrodes on the right and left armpits, and the reference electrode around the chest on a lead I configuration where the electrodes were embedded on a shoulder strap with Velcro. Measurement was carried out at static and dynamic conditions and results show that the ECG signals collected from the embroidered and silver printed textile electrodes have identifiable P, QRS, and T waveforms and have comparable signal quality with signals acquired using standard Ag/AgCl electrodes

Evaluation of silver-coated textile electrodes for ECG recording

Ag/AgCl gelled electrodes are often used for the ECG measurement, but they are not suitable for long-term monitoring due to dehydration of the gel over time and skin irritation. Textile-based electrodes could have an important role in replacing the gelled electrodes and avoid their associated problems. This study aims to measure ECG using silver-printed and embroidered textile electrodes and compare them against Ag/AgCl electrodes. ECG signals measured at the static condition and slow walking were analyzed and compared based on signal morphology, HR, and R-R interval. The results revealed that signals measured using all electrodes have visible P, QRS, and T waves, but in comparison, the embroidered textile electrodes have higher R-peak amplitude (1.28 mV) compared to silver printed textile and standard Ag/AgCl electrodes both at static and dynamic conditions. During walking, some distortion of signals was observed that would be due to unstable skin-electrode contact