Introduction: Early studies in piezoelectricity, pyroelectricity, and ferroelectricity in polymers

Abstract

Studies on piezoelectricity and pyroelectricity in polymers were initiated in materials of biological origin. A variety of polysaccharides, proteins and DNA were found to exhibit piezolectricity. Synthetic polymers such as polypeptides and optically-active polymers were also found to be piezoelectric. The piezolectricity and pyroelectricity in bone and tendon aroused interests in orthopaedists and led to studies on the electrical stimulation of osteogenesis. The discovery of large piezoelectricity in poled polyvinylidene fluoride opened a new field of research towards ferroelectric polymers. The Curie temperature was confirmed in the copolymers of vinylidene fluoride and trifluoroethylene. The characteristic changes of molecular conformation and associated crystalline structure were revealed at the temperature range of the phase transition. Piezoelectric and ferroelectric-like properties were found in the copolymers of vinylidenecyanide and vinylacetate, which are amorphous and transparent.