From 09/18/2014 through 3/7/2013
1. “Piezoelectricity (pron.: /piˌeɪzoʊˌilɛkˈtrɪsɪti/) is the electric charge that accumulates in certain solid materials (notably crystals, certain ceramics, and biological matter such as bone, DNA and various proteins) in response to applied mechanical stress. The word piezoelectricity means electricity resulting from pressure. It is derived from the Greek piezo or piezein (πιέζειν), which means to squeeze or press, and electric or electron (ήλεκτρον), which stands for amber, an ancient source of electric charge. Piezoelectricity was discovered in 1880 by French physicists Jacques and Pierre Curie.
The piezoelectric effect is understood as the linear electromechanical interaction between the mechanical and the electrical state in crystalline materials with no inversion symmetry. The piezoelectric effect is a reversible process in that materials exhibiting the direct piezoelectric effect (the internal generation of electrical charge resulting from an applied mechanical force) also exhibit the reverse piezoelectric effect (the internal generation of a mechanical strain resulting from an applied electrical field). For example, lead zirconate titanate crystals will generate measurable piezoelectricity when their static structure is deformed by about 0.1% of the original dimension. Conversely, those same crystals will change about 0.1% of their static dimension when an external electric field is applied to the material. The inverse piezoelectric effect is used in production of ultrasonic sound waves.
Piezoelectricity is found in useful applications such as the production and detection of sound, generation of high voltages, electronic frequency generation, microbalances, and ultrafine focusing of optical assemblies. It is also the basis of a number of scientific instrumental techniques with atomic resolution, the scanning probe microscopies such as STM, AFM, MTA, SNOM, etc., and everyday uses such as acting as the ignition source for cigarette lighters and push-start propane barbecue.”
(Piezoelectricity, Wikipedia, 3/7/2013)
2. Typical piezoelectric materials are PZT (PBZrO3--PbTiO3-based solid solution), which is a ceramic material. However, since PZT contains lead, potential toxicity is a problem. Because piezoelectric polymeric materials are generally electrically inferior to PZT, there is demand for improved polymer piezoelectric materials.
Yoshida et al of Mitsui Chemicals and Kansai University, Japan, developed a helical chiral polymer such as polylactic acid polymer with a weight average molecular weight of from 50,000 to 1,000,000,optical activity and 20 to 80 % crystallinity showing enhanced piezoelectricity.. This polymer can also be blended with polyvinylidene fluoride for piezoelectric materials.8,829,121 (9/9/2014)
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Roger D. Corneliussen
Maro Polymer Links
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Copyright 2013 by Roger D. Corneliussen.
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* Date of latest addition; date of first entry is 3/7/2013.