ABSTRACT
The symmetry of D", is observed for most natural biopolymers, which show only shear piezoelectricity. The 3 axis is taken as the axis of orientation. In this symmetry the relation ~ = -d14 holds. The symmetry of C", is found in certain structures of living systems such as bone and tendon. The preferred alignment of the polar axis of polymer crystallites in the 3 axis provides the piezoelectric constants d31 and d33 as well as the pyroelectric effect in the 3 axis, although they are not so large.
