Anisotropic electrical conduction in gum arabica - a biopolymer

Gum arabica, a natural biopolymer, exhibits electrical properties like conducting polymers. Earlier investigations show its ion-conducting superionic nature rather than its proton conducting nature with room temperature d.c. conductivity 10e-07 S/cm. The present study shows more interesting electrical characters gum arabica, XRD study of its powdered sample shows an amorphous nature and that of caste and textured specimen show an increased RDF. The same indicates a possibility of crystallization, which is a difficult task for this solid gel-like substance. Specimen with preferred molecular orientation is prepared by casting thin layer of gum arabica on scratched (similar to 10 mum) metal electrode and glass substrate. The desired anisotropy thus produced is confirmed by XRD study. The morphology of ordinarily caste specimen and textured specimen were studied and compared by SEM study. The impedance spectroscopy carried over this specimen shows an electrical conductivity like that of crystalline conducting polymer. Transverse and longitudinal electrical conductivity with their frequency dispersion show marked difference. Its further investigation and applications are under progress. (C) 2002 Elsevier Science B.V. All rights reserved.