Temperature-Dependence of Electrical Conductivity for Some Natural Coordination Polymeric Biomaterials Especially Some Cross-Linked Trivalent Metal-Alginate Complexes with Correlation between the Coordination Geometry and Complex Stability

摘要

The electrical conductivity (??) of cross-linked arsenic (III) - alginate complex as a coordination polymeric biomaterial in the form of circular discs have been measured as a function of temperature. The measured values of the electrical conductivity were found to be in the range of semiconductors. The change of electrical conductivity as a function of temperature was found to be of considerable complexity (Arrhenius plot of ln ?? vs. 1/T ). The appearance of a parabola zone at the early stages was explained by the release of waters of crystalline, whereas the sharp increase in ?? values observed at the elevated temperatures was interpreted by the degradation process of the complex to give rise to the metal oxide as final product. The X-ray diffraction patterns indicated that the metalalginate complex is amorphous in nature. Infrared absorption spectra revealed a sort of complexation between the trivalent metal cations and the functional carboxylate and hydroxyl groups of alginate macromolecule. A suitable conduction mechanism in terms of the complex stability in relation to the coordination geometry is suggested and discussed.