Piezoelectric textiles

Development techniques for energy harvesting piezoelectric textiles 366... 

In the following section, the three major routes most frequently explored and nsed for the deposition and creation of piezoelectric materials/piezoelectric textile stmctures are discussed. These include the electrochemical deposition of zinc oxide piezoelectric structures, electrospinning, and finally conventional melt-spinning, followed by two- and three-dimensional weaving. 

Nilsson, E., Mateu, L., Spies, P., Hagstrdm, B., 2014. Energy harvesting fiom piezoelectric textile fibers. Procedia Engineering 87, 1569—1572. 

A case study sewn piezoelectric textile devices for walking patterns... 

We have for a number of years developed polymer-based piezoelectric textile filaments and yarns [44]. Filaments are melt spun and bicomponents core-and-sheath type based on a blend of a normal bulk polymer like high-density polyethylene and the piezoelectric material (PVDF), surrounding a core of a conductive polyethylene-carbon black mixture (see Fig. 28.25). The core is electrically conductive and will act like an electrode. 

A. Lund, Melt Spun Piezoelectric Textile Fibres An Experimental study. Thesis for Degree of Doctor of Philosophy, Chalmers Univerisity of Technology, 2013. 

Knitted structures are made of loops of yam interconnected with each other. The size of the loop can be altered to produce a fabric as per required characteristics. Some knitted stmctures offer robusmess and are suitable for many technical applications. Knitted stmctures are mainly classed as weft knitted or warp knitted. Weft-knitted fabrics are highly stretchable and hence are extremely useful for undergarment and sportswear production. Warp-knitted fabrics do not unravel as easily as weft-knitted stmctures, and have significant insulating properties. In piezoelectric harvesting textiles, knitted stmctures offer extensibility, which is advantageous for wearable piezoelectric textiles, allowing wearer comfort. 

Functional fibres, filaments and yams are the basic building blocks of electrotextiles. The textile industry has demonstrated a remarkable capability to incorporate both natural and man-made filaments into yarns and fabrics to satisfy a wide range of physical parameters which survive the manufacturing process and are tailored to specific application environments. Electronic components can be fabricated within and/or on the surface of filaments and can subsequently be processed into functional yams and woven into fabrics. Passive components such as resistors, capacitors and inductors can be fabricated in several different manners. Diodes and transistors can be made on long, thin, flat strands of silicon or formed in a coaxial way. Progress has been made in the development of fibre batteries and fibre-based solar cells. In addition, a variety of actuated materials (piezoelectric, etc.) can be made into multiple long strands (filaments) and subsequently be woven into fabric. 

Physical/electrochemical deposition of piezoelectric materials on textiles... 

Hadimani RL, B ayramol DV, Soin N, Shah TH, Qian L, Shi S, et al. Continuous production of piezoelectric PVDF fibre for e-textile apphcations. Smart Mater Struct 2013 22(7) 075017. 

Khan A, Abbasi MA, Hussain M, Ibupoto ZH, Wissting J, Nur O, et al. Piezoelectric nanogenerator based on zinc oxide nanorods grown on textile cotton fabric. Appl Phys Lett 2012 10(19) 193506. 

Khan A, Hussain M, Nur O, Willander M. Mechanical and piezoelectric properties of zinc oxide nanorods grown on conductive textile fabric as an alternative substrate. J Phys D Appl Phys 2014 47(34) 345102. 

Nilsson E, Lund A, Jonasson C, Johansson C, Hagstrom B. Poling and characterization of piezoelectric polymer fibers for use in textile sensors. Sensor Actual A- Phys 2013 201 477-86. 

Figure 3. Heart beat signal acquired by piezoelectric film sensor (x-scale Time, y scale Volt). Respiratory rate Textiles used as extensioii sensor...

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