Regular Papers : Electrical Characteristics of Poly(ethylene oxide)-urea Complex Films

The electrical characteristics of complex films composed of poly(ethylene oxide) (PEO) and urea as a function of the urea concentration were examined in this study. Moreover, their structural characteristics were also compared. Depending on the urea concentration, the structural phases were classified as PEO+β-phase composite, β-phase+α- phase composites, or α-phase composite+urea. At urea concentrations below ~0.064 M, the β-phase was dominant in the complex film. Moreover, the conductance increased rapidly with an increase in the urea concentration. For urea concentrations ranging from ~0.064 to ~0.25 M, the β-phase was gradually substituted by the α-phase. As the film was composed entirely of the α-phase at urea concentrations greater than ~0.25 M, its conductance was decreased. In this study, the electrical characteristics observed for the different phases are analyzed and discussed.