Chaotic oscillation observed on the electric potential in artificial membranes doped with triolein and Span80

The electric potential in a membrane doped with triolein (glycerol trioleate)/Span80 (sorbitan monooleate) placed between 4 M/0.5 M NaCl and 4 M/0.5 M KCl aqueous solutions was investigated by using an FFT (fast Fourier transform), a return map and a phase-space portrait. These results show that there exists a critical potential which separates a simple oscillating state and a chaotic state in both cases. Moreover the first evidence of intermittency was found in the Span80-doped membrane system. Differences observed in the FFT spectra and the return maps between the electric potentials of these two membrane systems are discussed.