Electroactive polymer-based devices for e-textiles in biomedicine.
ABSTRACT This paper describes the early conception and latest developments of electroactive polymer (EAP)-based sensors, actuators, electronic components, and power sources, implemented as wearable devices for smart electronic textiles (e-textiles). Such textiles, functioning as multifunctional wearable human interfaces, are today considered relevant promoters of progress and useful tools in several biomedical fields, such as biomonitoring, rehabilitation, and telemedicine. After a brief outline on ongoing research and the first products on e-textiles under commercial development, this paper presents the most highly performing EAP-based devices developed by our lab and other research groups for sensing, actuation, electronics, and energy generation/storage, with reference to their already demonstrated or potential applicability to electronic textiles.
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ABSTRACT: In the present work the authors made textile sensors by the screen printing method with the use of carbon nanotubes. The sensors obtained are intended for monitoring dangers in direct contact with the body. For this reason the modification of carbon nanotube dispersion, with the commercial name AquaCyl from the Nanocyl company, was performed in order to give the textiles, apart from increased electric conductivity, bacteriostatic properties, which are extremely important in the case of biomaterials.Assessment of the efficiency of the sensors both for mechanical stimuli and the action of Gram-positive and Gram-negative bacteria was performed. The main advantages of this type of prod-uct are: n increased convenience of use; n high flexibility; n easiness of movement for the user, thanks to eliminating the rigid ele-ments (e.g. wires) connecting the sen-sors with the textiles; n dimensions of the sensors. Textiles with integrated modern sensors are used for assessing different changing parameters, such as pressure, stress and deformation [7 -10]. Biomedical products manufactured with the previously mentioned properties are utilised for monitoring the heart beating, making an electrocardiogram, and con-trolling the frequency of breathing or the pulse [11 -15]. Most modern sensors are based on mi-croelectronics or conductive polymers, which are integrated with the structure of materials or fibrous structures. In the future, utilising electronic systems to make intelligent clothing will be an integral part of everyday wear . Printing is considered attractive technol-ogy in the range of the possible construc-tion of electroconductive paths, leading to the creation of intelligent products. The printing technology of electrocon-ductive paths has wide application in microelectronics, but is mainly used on plates, films, glass and on polymers. Most of the conductive inks used contain nanoparticles of silver, gold, copper, their compositions, and silver nitrate [17 -21]. The limitation of this process for appli-cation in textiles is the necessity of us-ing high temperature annealing in most cases over 200 o C. Recently research has been carried out on obtaining Ink com-positions, giving conductive properties at temperatures of about 70 °C [22 -27].
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ABSTRACT: Wearable electronics offer the combined advantages of both electronics and fabrics. Being an indispensable part of these electronics, lightweight, stretchable and wearable power sources are strongly demanded. Here we describe a daily-used cotton fabric coated with polypyrrole as electrode for stretchable supercapacitors. Polypyrrole was synthesized on the Au coated fabric via an electrochemical polymerization process with p-toluenesulfonic acid (p-TS) as dopant from acetonitrile solution. This material was characterized with FESEM, tensile stress, and studied as a supercapacitor electrode in 1.0 M NaCl. This conductive textile electrode can sustain up to 140% strain without electric failure. It delivers a high specific capacitance of 254.9 Fg(-1) at a scan rate of 10 mV s(-1), and keeps almost unchanged at an applied strain (i.e. 30% and 50%) but with an improved cycling stability.Electrochimica Acta 12/2013; 113:17-22. DOI:10.1016/j.electacta.2013.09.024 · 4.09 Impact Factor
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ABSTRACT: Dielectric elastomer generators (DEGs) are light, compliant, silent energy scavengers. They can easily be incorporated into clothing where they could scavenge energy from the human kinetic movements for biomedical applications. Nevertheless, scavengers based on dielectric elastomers are soft electrostatic generators requiring a high voltage source to polarize them and high external strain, which constitutes the two major disadvantages of these transducers. We propose here a complete structure made up of a strain absorber, a DEG and a simple electronic power circuit. This new structure looks like a patch, can be attached on human’s wear and located on the chest, knee, elbow… Our original strain absorber, inspired from a sailing boat winch, is able to heighten the external available strain with a minimal factor of 2. The DEG is made of silicone Danfoss Polypower and it has a total area of 6cm per 2.5cm sustaining a maximal strain of 50% at 1Hz. A complete electromechanical analytical model was developed for the DEG associated to this strain absorber. With a poling voltage of 800V, a scavenged energy of 0.57mJ per cycle is achieved with our complete structure. The performance of the DEG can further be improved by enhancing the imposed strain, by designing a stack structure, by using a dielectric elastomer with high dielectric permittivity.SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring; 03/2014