Characteristic length scale of bicontinuous nanoporous structure by fast Fourier transform

We propose a method derived from fast Fourier transform (FFT) process to measure the characteristic length scale of bicontinuous nanoporous structures. By rotationally averaging the FFT power spectrum of a nanoporous micrograph from scanning electron microscope (SEM) or transmission electron microscope (TEM), a significant peak in the power spectrum can be obtained, which reflects the characteristic length scale of the quasi-periodic structure. This method is demonstrated for the bicontinuous morphology that is frequently observed in nanoporous metals prepared by chemical or electrochemical dealloying.