Study of the piezoelectricity in iron-doped collagen films

In this paper a study was carried out of collagen membranes prepared with iron as an impurity. In this study the function of the iron in the collagen structure was examined with the aim of increasing the value of the piezoelectric strain tensor element d14. We prepared different samples with different iron doping levels. Doped samples by immersion in solutions of FeCl2 (0.1 M and 0.2 M), FeCl3 (0.1 M) and FeNH4SO4 (0.1 M) and iron doped directly in solution with Fe2O3 at 5% and 15% were examined. Mossbauer spectroscopy, the piezoelectric strain tensor element d14 the elastic constant s55, and the dielectric function ɛ11 of the samples were examined. The loss factor Q−1 of the samples was also measured using the admittance resonance method. The role played by the iron in the different situations and the consequences for the transport properties are discussed.