PROPERTIES OF FLUORIDE-CONTAINING POLYMER-FILMS WITH PIEZOACTIVITY AND PYROACTIVITY

Properties of polymer films based on polyvinylidendfluoride and its copolymers, which can reveal piezo- and pyroactivity after specific treating are described. One of the basic advantages of this class of materials is the high value of piezomodules, permitting to use them in practice. Another valuable peculiarity that is hard to realise using nonorganic materials is a broad frequency band in which the active element can work. The possibility of obtaining large surfaces and rather simple ways of small thickness film realisation also make them promising for creating new transducers. The tendencies are shown in the development of new devices based on the materials mentioned, where the phenomena of photopyroelectric activity is used. The advantages of the given materials for medical applications are also described. Together with the noted properties, the film flexibility and acoustic impedance, which is close to that in biological tissue, makes it superconcurent as compared with other materials. Taking the ferroelectric nature of these polymers into account, they look promising for nonlinear optics applications.